An inch is exactly 2.54 cm, a foot is 12 inches (30.48 cm), a yard is 3 feet (0.9144 m) and a mile is 5,280 feet, 1,760 yards or exactly 1.609344 km. A meter is 3.28 feet, a 5K race is 3.107 miles, and an acre is 43,560 square feet.
Quick reference: length, distance and area chart
| Unit | US customary | Metric | Reverse |
|---|---|---|---|
| 1 inch | 1/12 ft | 2.54 cm = 25.4 mm | 1 cm = 0.3937 in |
| 1 foot | 12 in | 30.48 cm = 0.3048 m | 1 m = 3.28084 ft |
| 1 yard | 3 ft = 36 in | 0.9144 m | 1 m = 1.0936 yd = 39.37 in |
| 1 mile | 5,280 ft = 1,760 yd = 63,360 in | 1,609.344 m = 1.609344 km | 1 km = 0.621371 mi = 3,280.84 ft |
| 5K race (5 km) | 3.107 mi = 16,404 ft = 5,468 yd | 5,000 m | 12.5 laps of a 400 m track |
| Marathon (42.195 km) | 26.219 mi (26 mi 385 yd) | 42,195 m | Half marathon: 21.0975 km = 13.109 mi |
| 1 square yard | 9 sq ft | 0.8361 m² | |
| 1 acre | 43,560 sq ft = 4,840 sq yd | 4,046.8564 m² = 0.4047 ha | 1 ha = 2.4711 acres |
| 1 square mile | 640 acres = 27,878,400 sq ft | 2.59 km² |
All values use the international foot (exactly 0.3048 m) and inch (exactly 0.0254 m) from NIST SP 811, Appendix B.8, so the metric figures for the inch, foot, yard and mile are exact. Race distances follow World Athletics. Each section below covers one conversion in detail.
How many centimeters in an inch?
One inch is exactly 2.54 centimeters. To convert inches to centimeters, multiply by 2.54; to convert centimeters to inches, divide by 2.54. So 12 inches is 30.48 cm, and 10 cm is 3.937 inches. In millimeters, one inch is 25.4 mm.
NIST Appendix B.8 lists the inch as exactly 0.0254 meter. A centimeter is one hundredth of a meter, so an inch is 2.54 cm, and a millimeter is 1/25.4 of an inch (0.03937 in). Because the inch is defined this way, the factor is exact and needs no rounding.
Formulas: centimeters in an inch
centimeters = inches × 2.54
inches = centimeters ÷ 2.54 (or centimeters × 0.393701)
millimeters = inches × 25.4
Use the inches to cm converter, the mm to inches and inches to mm pages, or centimeters to feet.
Inches to centimeters chart
| Inches | Centimeters |
|---|---|
| 1/8 | 0.318 |
| 1/4 | 0.635 |
| 1/2 | 1.27 |
| 1 | 2.54 |
| 2 | 5.08 |
| 5 | 12.7 |
| 6 | 15.24 |
| 12 (1 ft) | 30.48 |
| 36 (1 yd) | 91.44 |
| 60 | 152.4 |
| 72 (6 ft) | 182.88 |
Centimeters to inches chart
| Centimeters | Inches |
|---|---|
| 1 | 0.394 |
| 5 | 1.969 |
| 10 | 3.937 |
| 30 | 11.811 |
| 50 | 19.685 |
| 100 | 39.370 |
| 150 | 59.055 |
| 170 | 66.929 |
| 180 | 70.866 |
Worked examples: centimeters in an inch
Example 1: height in feet and inches
A height of 170 cm is 170 ÷ 2.54 = 66.93 inches. Divide by 12: 5 whole feet (60 in) with 6.93 inches left, so 5 ft 6.93 in, close to 5 ft 7 in. Going the other way, 5 ft 9 in is 69 × 2.54 = 175.26 cm.
Example 2: a 30 cm ruler
A 30 cm ruler is 30 ÷ 2.54 = 11.81 inches, a little shorter than a 12-inch ruler (30.48 cm), a difference of 0.48 cm.
Example 3: fractions of an inch
A 3/8-inch bolt is 0.375 × 2.54 = 0.9525 cm, or 9.525 mm. To read such fractions on a tape, see how to read a tape measure.
Example 4: screen and paper sizes
A 15.6-inch laptop screen has a diagonal of 15.6 × 2.54 = 39.62 cm. A letter sheet is 8.5 × 11 in, or 21.59 × 27.94 cm.
Quick ways to estimate: centimeters in an inch
- Inches to cm: multiply by 2.5 and add 1.6%, or double and add half (10 in: 20 + 5 = 25 cm, against 25.4 exact).
- Cm to inches: multiply by 0.4 and subtract 1.6% (50 cm: 20 − 0.32 = 19.68 in, against 19.69).
- Landmarks: 2.54 cm is one inch, 30.48 cm is one foot, 91.44 cm is one yard.
For related pairs see the metric vs imperial guide and all unit converters.
How many inches in a foot?
A foot is exactly 12 inches. To convert feet to inches, multiply by 12 (5 feet is 60 inches); to convert inches to feet, divide by 12 (96 inches is 8 feet). Because the international foot is defined as 0.3048 meters and the inch as 2.54 centimeters, a foot is also exactly 30.48 cm.
NIST lists the foot as 0.3048 m and the inch as 0.0254 m, both exact. Dividing, 0.3048 ÷ 0.0254 = 12. Every length in feet therefore has 12 times as many inches. For other values use feet to inches or inches to feet.
Feet to inches chart
| Feet | Inches | Centimeters |
|---|---|---|
| 1/4 | 3 | 7.62 |
| 1/2 | 6 | 15.24 |
| 1 | 12 | 30.48 |
| 2 | 24 | 60.96 |
| 3 (1 yard) | 36 | 91.44 |
| 4 | 48 | 121.92 |
| 5 | 60 | 152.4 |
| 6 | 72 | 182.88 |
| 7 | 84 | 213.36 |
| 10 | 120 | 304.8 |
Worked examples: inches in a foot
Example 1: feet and inches to inches
A height of 5 ft 9 in is 5 × 12 + 9 = 69 inches, or 69 × 2.54 = 175.26 cm. The feet to cm converter does the same in one step.
Example 2: inches to feet and inches
A 87-inch curtain rod: 87 ÷ 12 = 7.25, so 7 feet with 0.25 × 12 = 3 inches left over, 7 ft 3 in.
Example 3: decimal feet
A plan lists 6.5 ft. The 0.5 is half a foot, so 6.5 × 12 = 78 inches, or 6 ft 6 in. Decimal feet are not feet-and-inches: 5.6 ft is 5.6 × 12 = 67.2 inches, which is 5 ft 7.2 in, not 5 ft 6 in.
How do feet relate to yards and miles?
| Unit | Feet | Inches |
|---|---|---|
| Foot | 1 | 12 |
| Yard | 3 | 36 |
| Mile | 5,280 | 63,360 |
A mile is 1,760 yards × 36 = 63,360 inches, and 63,360 × 0.0254 = 1,609.344 meters.
Quick ways to remember: inches in a foot
- 12 inches, one ruler: a standard ruler is often marked as 12 inches, which is a foot.
- Times 12: to turn a height such as 6 ft 2 in into inches, do 6 × 12 = 72, then add 2 for 74.
- Metric check: a foot is just over 30 cm, so 3 feet is just under a meter (91.44 cm).
- 100 inches is 100 ÷ 12 = 8.333 feet, which is 8 feet 4 inches.
To read the fractions between the inch marks, see how to read a tape measure; for systems side by side, see metric vs imperial.
How many feet in a yard?
A yard is exactly 3 feet. To convert yards to feet, multiply by 3 (7 yards is 21 feet); to convert feet to yards, divide by 3 (12 feet is 4 yards). A yard is also 36 inches and exactly 0.9144 meters, slightly shorter than a meter.
NIST gives the yard as 0.9144 m and the foot as 0.3048 m, both exact. 0.9144 ÷ 0.3048 = 3. Use yards to feet or feet to yards for any other value.
Yards to feet chart
| Yards | Feet | Inches | Meters |
|---|---|---|---|
| 1 | 3 | 36 | 0.9144 |
| 2 | 6 | 72 | 1.8288 |
| 5 | 15 | 180 | 4.572 |
| 10 | 30 | 360 | 9.144 |
| 25 | 75 | 900 | 22.86 |
| 50 | 150 | 1,800 | 45.72 |
| 100 | 300 | 3,600 | 91.44 |
| 1,760 (1 mile) | 5,280 | 63,360 | 1,609.344 |
Worked examples: feet in a yard
Example 1: a fabric or fence length
A fence run is 45 feet: 45 ÷ 3 = 15 yards. Fabric sold by the yard, 4.5 yards, is 4.5 × 3 = 13.5 feet or 162 inches.
Example 2: yards and feet together
A distance of 23 yards 2 feet is 23 × 3 + 2 = 71 feet. Going back, 71 ÷ 3 = 23.667 yards, which is 23 yards and 2 feet.
Example 3: yards to meters
100 yards × 0.9144 = 91.44 meters, so a 100-yard distance is about 8.6 meters short of 100 m.
What about square and cubic yards?
Area and volume scale with the square and cube of the length. One square yard is 3 × 3 = 9 square feet, and one cubic yard is 3 × 3 × 3 = 27 cubic feet. This matters for mulch, soil and concrete, which are sold by the cubic yard: a 1.5 cubic yard order is 1.5 × 27 = 40.5 cubic feet. The cubic yard calculator converts a bed size straight to yards.
Quick ways to remember: feet in a yard
- Three feet to the yard: a yard is a bit less than a meter, so 3 feet is just under 1 m.
- Yards to feet: triple it. 8 yards is 24 feet.
- Cubes are cubed: 27 cubic feet per cubic yard, not 3.
How many feet in a meter?
One meter is 3.2808 feet. NIST defines the foot as exactly 0.3048 m, so meters ÷ 0.3048 (or meters × 3.28084) gives feet. For example, 2 m is 6.56 ft and 10 m is 32.81 ft. In feet and inches, one meter is 3 ft 3.37 in, because a meter is 39.37 inches.
The international foot is defined as exactly 0.3048 meters (NIST SP 811, Appendix B.8), and the inch as exactly 0.0254 m. Dividing, 1 ÷ 0.3048 = 3.280840 feet, and 1 ÷ 0.0254 = 39.3701 inches. A meter is therefore a little over 3 feet 3 inches.
Formulas: feet in a meter
feet = meters ÷ 0.3048 (or meters × 3.28084)
meters = feet × 0.3048
inches = meters × 39.3701
yards = meters × 1.09361
Converters: meters to feet, feet to meters, meters to inches, meters to yards and feet to cm.
Meters to feet chart
| Meters | Feet | Yards |
|---|---|---|
| 1 m | 3.28 | 1.09 |
| 2 m | 6.56 | 2.19 |
| 3 m | 9.84 | 3.28 |
| 5 m | 16.40 | 5.47 |
| 10 m | 32.81 | 10.94 |
| 50 m | 164.04 | 54.68 |
| 100 m | 328.08 | 109.36 |
| 400 m | 1,312.34 | 437.45 |
| 1,000 m (1 km) | 3,280.84 | 1,093.61 |
Feet to meters chart
| Feet | Meters |
|---|---|
| 1 ft | 0.3048 |
| 5 ft | 1.524 |
| 6 ft | 1.8288 |
| 10 ft | 3.048 |
| 20 ft | 6.096 |
| 100 ft | 30.48 |
Heights in meters to feet and inches
| Height | Feet | Feet and inches |
|---|---|---|
| 1.5 m | 4.92 | 4 ft 11.1 in |
| 1.6 m | 5.25 | 5 ft 3.0 in |
| 1.7 m | 5.58 | 5 ft 6.9 in |
| 1.75 m | 5.74 | 5 ft 8.9 in |
| 1.8 m | 5.91 | 5 ft 10.9 in |
| 1.9 m | 6.23 | 6 ft 2.8 in |
| 2.0 m | 6.56 | 6 ft 6.7 in |
Worked examples: feet in a meter
Example 1: a room size
A room is 4 m by 5 m. In feet that is 4 ÷ 0.3048 = 13.12 ft by 5 ÷ 0.3048 = 16.40 ft, a floor area of 215.3 square feet (20 m² × 10.7639).
Example 2: a height
A person who is 1.75 m tall is 1.75 ÷ 0.3048 = 5.741 ft. The decimal part, 0.741 × 12 = 8.9 inches, so the height is 5 ft 8.9 in. Writing it as "5.74 ft" and reading it as 5 ft 74 in is a common mistake.
Example 3: a track
A 400 m track is 400 ÷ 0.3048 = 1,312.3 ft, or 437.4 yards. One lap is therefore about 0.249 miles (1,312.34 ÷ 5,280); four laps cover 1,600 m, a bit short of the 1,609.344 m in a mile, described in how many feet in a mile.
Example 4: ceiling height
A 2.4 m ceiling is 2.4 ÷ 0.3048 = 7.87 ft, or 7 ft 10.5 in. A US standard 8-foot ceiling is 8 × 0.3048 = 2.438 m, 3.8 cm taller.
Example 5: a cable length
A 10 ft cable is 3.048 m. A 3 m cable is 9.84 ft, 0.16 ft (1.9 in) shorter than the 10 ft one, which matters when the plug has to reach a wall socket.
Is a meter longer than a yard?
Yes. A yard is exactly 0.9144 m (NIST), so 1 ÷ 0.9144 = 1.0936 yards per meter, which makes the meter about 9.4% longer. The two are close enough that 100 m (109.4 yd) and a 100-yard dash (91.44 m) differ by 8.56 m.
Quick ways to remember: feet in a meter
- 1 m is about 3.3 ft (3.28), and 1 ft is about 30 cm.
- For rough work, multiply by 3 and add 10%: 5 m ≈ 15 + 1.5 = 16.5 ft, against the exact 16.40.
- For heights, convert the fraction of a foot to inches separately (× 12).
- Check the system: the metric vs imperial guide lists the common conversions, and how to read a tape measure explains both scales.
How many feet in a mile?
A mile contains 5,280 feet, which is also 1,760 yards. To convert miles to feet, multiply by 5,280: 2 miles is 10,560 feet, and half a mile is 2,640 feet. To go from feet to miles, divide by 5,280, so 10,000 feet is about 1.89 miles.
The mile used in everyday US distances is the statute mile. NIST lists it as exactly 1,609.344 meters. The international foot is exactly 0.3048 m, and dividing one by the other gives 1,609.344 ÷ 0.3048 = 5,280 feet. Because a yard is 3 feet, that is 5,280 ÷ 3 = 1,760 yards. Inches follow too: 5,280 × 12 = 63,360 inches.
Miles to feet chart
| Miles | Feet | Yards | Meters |
|---|---|---|---|
| 1/8 mile | 660 | 220 | 201.17 |
| 1/4 mile | 1,320 | 440 | 402.34 |
| 1/2 mile | 2,640 | 880 | 804.67 |
| 3/4 mile | 3,960 | 1,320 | 1,207.01 |
| 1 mile | 5,280 | 1,760 | 1,609.34 |
| 2 miles | 10,560 | 3,520 | 3,218.69 |
| 3.1 miles (about 5K) | 16,368 | 5,456 | 4,988.97 |
| 5 miles | 26,400 | 8,800 | 8,046.72 |
| 10 miles | 52,800 | 17,600 | 16,093.44 |
The converters miles to feet, feet to miles, miles to yards and miles to km cover other values, and feet to meters handles the foot on its own.
How do I convert feet to miles?
Divide by 5,280. A few common conversions:
| Feet | Miles (decimal) | Fraction |
|---|---|---|
| 500 ft | 0.095 | about 1/10 |
| 1,000 ft | 0.189 | about 1/5 |
| 2,000 ft | 0.379 | about 3/8 |
| 2,640 ft | 0.5 | 1/2 |
| 5,000 ft | 0.947 | about 19/20 |
| 10,000 ft | 1.894 | about 1 9/10 |
Worked examples: feet in a mile
Example 1: a hiking trail in feet
A trail sign says 18,480 feet to the summit. 18,480 ÷ 5,280 = 3.5 miles. The reverse check: 3.5 × 5,280 = 18,480 ✓.
Example 2: elevation against distance
A 12,000-foot distance is 12,000 ÷ 5,280 = 2.27 miles. A path that climbs 500 feet over that distance rises about 500 ÷ 12,000 = 4.2% of its length.
Example 3: a 5K in feet
A 5K race is 5 kilometers, or 5,000 m. 5,000 ÷ 0.3048 = 16,404 feet, which is 16,404.2 ÷ 5,280 = 3.107 miles. Rounding a 5K to 3.1 miles, as in the table above, leaves out about 36 feet (3.107 − 3.1 = 0.007 mi).
Example 4: kilometers to miles for a road sign
A sign shows 50 km. 50 ÷ 1.609344 = 31.07 miles, or 164,042 feet (50,000 ÷ 0.3048).
Example 5: laps on a quarter-mile track
A track lap of a quarter mile is 1,320 feet. To run a mile takes 5,280 ÷ 1,320 = 4 laps; for 3 miles, 12 laps.
What is the difference between the statute mile and the survey mile?
A survey mile, based on the retired US survey foot, measured 1,609.347 m against 1,609.344 m for the statute mile, about 3 mm per mile; the details are under international vs survey foot.
Is a nautical mile the same as a mile?
No. A nautical mile is a separate unit used in sea and air navigation, longer than the 5,280-foot statute mile. The converter nautical miles to miles shows the exact relationship, and the metric vs imperial guide explains why unit names that sound alike can cause real errors.
Quick ways to remember: feet in a mile
- 5,280 feet = 1 mile, and 1,760 yards = 1 mile.
- Quarter-mile chunks are 1,320 ft: a quarter, half and three-quarter mile are 1,320, 2,640 and 3,960 ft.
- 1 mile is about 1.6 km, and 1 km is about 0.62 miles; the tape measure guide covers the small end of the same system, the inch.
How many yards in a mile?
A mile is exactly 1,760 yards. To convert miles to yards, multiply by 1,760 (3 miles is 5,280 yards); to convert yards to miles, divide by 1,760 (880 yards is half a mile). The mile also equals 5,280 feet and exactly 1,609.344 meters.
NIST lists the mile as 1,609.344 m and the yard as 0.9144 m, both exact. 1,609.344 ÷ 0.9144 = 1,760. The same mile is 5,280 feet, since 1,760 × 3 = 5,280. Use miles to yards or yards to miles for other values.
Miles to yards chart
| Miles | Yards | Feet | Meters |
|---|---|---|---|
| 1/8 | 220 | 660 | 201.168 |
| 1/4 | 440 | 1,320 | 402.336 |
| 1/2 | 880 | 2,640 | 804.672 |
| 3/4 | 1,320 | 3,960 | 1,207.008 |
| 1 | 1,760 | 5,280 | 1,609.344 |
| 2 | 3,520 | 10,560 | 3,218.688 |
| 5 | 8,800 | 26,400 | 8,046.72 |
| 10 | 17,600 | 52,800 | 16,093.44 |
Worked examples: yards in a mile
Example 1: miles to yards
A 10-mile route is 10 × 1,760 = 17,600 yards.
Example 2: yards to miles
A course of 3,000 yards is 3,000 ÷ 1,760 = 1.705 miles, or 1 mile and 1,240 yards.
Example 3: a 5K in yards
5 kilometers is 5,000 m. 5,000 ÷ 0.9144 = 5,468 yards, and 5,468 ÷ 1,760 = 3.107 miles.
Where does 1,760 come from?
Today the units are fixed by metric definitions: the yard is exactly 0.9144 m and the mile exactly 1,609.344 m, so the ratio 1,609.344 ÷ 0.9144 = 1,760 is exact and does not change with rounding.
Quick ways to remember: yards in a mile
- Quarter-mile steps: 440, 880, 1,320, 1,760. Each quarter mile adds 440 yards.
- Yards to feet to miles: 1,760 yards × 3 = 5,280 feet.
- Metric check: a mile is about 1.6 km, so 1,760 yards is just over 1,600 m.
- 1,000 yards is 1,000 ÷ 1,760 = 0.568 miles.
For speeds over a mile use the pace calculator.
How many meters in a mile?
One mile is 1,609.344 meters exactly. To convert miles to meters, multiply by 1,609.344; to convert meters to miles, divide by 1,609.344. So 2 miles is 3,218.688 m, and 1,000 m is 0.6214 miles. Everyday usage rounds the figure to about 1,609 m.
NIST Appendix B.8 lists the mile as exactly 1,609.344 meters. It follows from 5,280 feet × 0.3048 m and equally from 1,760 yards × 0.9144 m (see foot and yard). Dividing by 1,000 gives 1.609344 kilometers; the full chart is in how many kilometers in a mile.
Formulas: meters in a mile
meters = miles × 1,609.344
miles = meters ÷ 1,609.344 (or meters × 0.000621371)
Use the miles to meters and meters to miles converters, or miles to feet.
Miles to meters chart
| Miles | Meters |
|---|---|
| 0.25 | 402.336 |
| 0.5 | 804.672 |
| 1 | 1,609.344 |
| 2 | 3,218.688 |
| 3.1 | 4,988.966 |
| 5 | 8,046.72 |
| 10 | 16,093.44 |
| 13.1 | 21,082.406 |
| 26.2 | 42,164.813 |
Meters to miles chart
| Meters | Miles |
|---|---|
| 100 | 0.0621 |
| 400 | 0.2485 |
| 800 | 0.4971 |
| 1,000 | 0.6214 |
| 1,500 | 0.9321 |
| 1,600 | 0.9942 |
| 3,000 | 1.8641 |
| 5,000 | 3.1069 |
Worked examples: meters in a mile
Example 1: laps of a track
A standard track lap is 400 m, so a mile is 1,609.344 ÷ 400 = 4.02 laps. Four laps cover 1,600 m, which leaves 9.344 m to reach a mile.
Example 2: the 1,500 m "metric mile"
1,500 ÷ 1,609.344 = 0.932 miles. The distance is 109.344 m short of a mile, which is about a quarter of a lap.
Example 3: a 5K in meters and miles
5 km is 5,000 m, or 5,000 ÷ 1,609.344 = 3.107 miles. More race distances are in how many miles is a 5K.
Example 4: a hike
A 3.5-mile trail is 3.5 × 1,609.344 = 5,632.7 m, or 5.63 km. At 4.8 km/h that is a little over an hour.
Quick ways to estimate: meters in a mile
- Miles to meters: multiply by 1,600 (0.6% low) or 1.6 and then by 1,000.
- Meters to miles: divide by 1,600, or multiply by 0.000625.
- 1,600 m is only 9.3 m (0.58%) short of a mile, so four laps of a 400 m track are a close stand-in for a mile.
See also the pace calculator and all unit converters.
How many kilometers in a mile?
One mile is 1.609344 kilometers, an exact value in NIST's conversion tables, and is normally rounded to 1.61 km. To convert miles to kilometers, multiply by 1.609344: 5 miles is 8.047 km and 10 miles is 16.093 km. To go the other way, divide by 1.609344, so 10 km is 6.214 miles.
NIST SP 811, Appendix B.8 lists the mile as exactly 1,609.344 meters, which is 1.609344 kilometers. The mile is therefore 1,609.344 m, and a kilometer (1,000 m, the prefix "kilo" meaning 10³) is 1 ÷ 1.609344 = 0.621371 miles.
Formulas: kilometers in a mile
kilometers = miles × 1.609344
miles = kilometers ÷ 1.609344 (or kilometers × 0.621371)
meters = miles × 1,609.344
Use the miles to km converter for any value, or miles to meters and km to feet for other units.
Miles to kilometers chart
| Miles | Kilometers |
|---|---|
| 0.5 | 0.805 |
| 1 | 1.609 |
| 2 | 3.219 |
| 3 | 4.828 |
| 5 | 8.047 |
| 10 | 16.093 |
| 13.1 | 21.082 |
| 26.2 | 42.165 |
| 50 | 80.467 |
| 100 | 160.934 |
Kilometers to miles chart
| Kilometers | Miles |
|---|---|
| 1 | 0.621 |
| 2 | 1.243 |
| 3 | 1.864 |
| 5 | 3.107 |
| 10 | 6.214 |
| 15 | 9.321 |
| 20 | 12.427 |
| 50 | 31.069 |
| 100 | 62.137 |
Speed limits and road signs
Speeds convert with the same factor. A limit of 100 km/h is 100 ÷ 1.609344 = 62.14 mph, 120 km/h is 74.56 mph and 80 km/h is 49.71 mph. In the other direction, 60 mph is 96.56 km/h and 70 mph is 112.65 km/h. Converters: mph to kph and kph to mph.
Worked examples: kilometers in a mile
Example 1: a 5K and a 10K
A 5 km race is 5 ÷ 1.609344 = 3.107 miles; a 10 km race is 6.214 miles. A runner holding a pace of 8:00 per mile covers 5 km in about 3.107 × 8 = 24.9 minutes. The pace calculator handles paces in either unit.
Example 2: a road trip
A trip of 250 miles is 250 × 1.609344 = 402.3 km. A sign reading 400 km in a country that uses kilometers is 400 ÷ 1.609344 = 248.5 miles.
Example 3: fuel economy distance
A car's 25-mile commute is 25 × 1.609344 = 40.2 km one way, so 80.5 km round trip.
Example 4: a treadmill
A treadmill that displays 3.1 miles has covered 3.1 × 1.609344 = 4.99 km, essentially 5 km.
Quick ways to estimate: kilometers in a mile
- Miles to km: multiply by 1.6, or add half and then one-tenth (10 mi: 10 + 5 + 1 = 16 km, against the exact 16.09).
- Km to miles: multiply by 0.6 and add a little (100 km: 60 + 2 = 62 miles).
For other everyday unit pairs see the metric vs imperial guide and the full list of unit converters.
How many miles is a 5K?
A 5K is 3.107 miles: 5 kilometers divided by 1.609344 kilometers per mile. The common shorthand of 3.1 miles is a rounded value. The same division gives 6.214 miles for a 10K, 13.109 miles for a half marathon and 26.219 miles for a marathon.
5K, 10K, half marathon and marathon in miles
The "K" in a race name is a kilometer. NIST lists the mile as exactly 1,609.344 meters, so miles = kilometers ÷ 1.609344. World Athletics gives the half marathon as 13.1094 miles or 21.0975 km, and the marathon as 26 miles and 385 yards (42.195 km), a distance it says was standardised in 1921.
| Race | Kilometers | Miles | Miles (as usually quoted) |
|---|---|---|---|
| 5K | 5 | 3.107 | 3.1 |
| 10K | 10 | 6.214 | 6.2 |
| 15K | 15 | 9.321 | 9.3 |
| 10 miles | 16.093 | 10 | 10 |
| Half marathon | 21.0975 | 13.109 | 13.1 |
| Marathon | 42.195 | 26.219 | 26.2 |
For any other distance use the miles to km converter or the km to miles converter.
What is 5K in miles, step by step?
- Take the distance in kilometers: 5.
- Divide by 1.609344 (or multiply by 0.621371).
- 5 ÷ 1.609344 = 3.1069 miles.
The marathon works the same way: 42.195 ÷ 1.609344 = 26.2188, which matches 26 miles + 385 yards (26 + 385/1,760 = 26.21875).
How many laps and meters is that?
A 5K is 5,000 meters, so it is 12.5 laps of a standard 400 m track. Laps per mile are worked out under how many meters in a mile.
How long does a 5K take at a given pace?
Finish time = distance in miles × pace per mile.
| Pace per mile | 5K (3.107 mi) | 10K (6.214 mi) | Marathon (26.219 mi) |
|---|---|---|---|
| 8:00 | 24 min 51 s | 49 min 42 s | 3 h 29 min 45 s |
| 10:00 | 31 min 4 s | 62 min 8 s | 4 h 22 min 11 s |
| 12:00 | 37 min 17 s | 74 min 34 s | 5 h 14 min 38 s |
Example: at 10:00 per mile, 3.1069 × 10 = 31.07 minutes, or 31 minutes 4 seconds. The pace calculator converts between pace, speed and finish time in miles or kilometers.
Why do some sources say 26.2 and others 26.22 miles?
Both are roundings of 26.21875 miles. Using 26.2 miles instead of the exact value understates the marathon by about 0.019 miles (30 m); using 3.1 miles for a 5K understates it by 0.007 miles (about 11 m). That is irrelevant for pacing but worth knowing when comparing a GPS watch reading with the official distance.
Metric and imperial distances side by side
Many US races are labelled in kilometers (5K, 10K) while training logs use miles. A runner who plans "3 miles" is covering 4.828 km, so a 5K is a little farther than a 3-mile run. See how many kilometers in a mile for the full chart and metric vs imperial for the wider picture, or browse all unit converters.
This page is for reference and is educational, not medical or training advice.
How many square feet in an acre?
One acre is 43,560 square feet. NIST's Handbook 44 defines it as 43,560 ft², equal to 160 square rods or 10 square chains. To convert acres to square feet, multiply by 43,560: 2 acres is 87,120 ft². To convert square feet to acres, divide by 43,560: a 10,000 ft² lot is 0.2296 acre.
The acre is a US customary unit of area. NIST lists it as 43,560 ft², and the square foot is exactly 0.09290304 m² on the international foot. Multiplying gives 43,560 × 0.09290304 = 4,046.8564 m², which is 0.40468564 hectare. The acre therefore sits between the square yard and the square mile:
| Unit | In square feet |
|---|---|
| 1 square yard | 9 |
| 1 acre | 43,560 (4,840 square yards) |
| 1 square mile | 27,878,400 (640 acres) |
The number looks odd because the acre was never built from a square. It comes from a strip 1 furlong long (660 ft) and 1 chain wide (66 ft): 660 × 66 = 43,560.
Formulas: square feet in an acre
square feet = acres × 43,560
acres = square feet ÷ 43,560
square meters = acres × 4,046.8564
hectares = acres × 0.40468564
Converters: acres to square feet, square feet to acres, acres to hectares, hectares to acres and square feet to square meters.
Acres to square feet chart
| Acres | Square feet | Square meters |
|---|---|---|
| 1/8 | 5,445 | 505.9 |
| 1/4 | 10,890 | 1,011.7 |
| 1/2 | 21,780 | 2,023.4 |
| 1 | 43,560 | 4,046.9 |
| 2 | 87,120 | 8,093.7 |
| 2.5 | 108,900 | 10,117.1 |
| 5 | 217,800 | 20,234.3 |
| 10 | 435,600 | 40,468.6 |
| 40 | 1,742,400 | 161,874.3 |
| 100 | 4,356,000 | 404,685.6 |
Square feet to acres chart
| Square feet | Acres |
|---|---|
| 5,000 | 0.1148 |
| 8,000 | 0.1837 |
| 10,000 | 0.2296 |
| 15,000 | 0.3444 |
| 21,780 | 0.5000 |
| 43,560 | 1.0000 |
Worked examples: square feet in an acre
Example 1: a quarter-acre lot
A quarter acre is 43,560 ÷ 4 = 10,890 ft². A rectangle of 90 ft by 121 ft has that area (90 × 121 = 10,890), but so does a lot of 100 ft by 108.9 ft.
Example 2: a lot measured in feet
A lot of 100 ft by 150 ft is 15,000 ft². Divided by 43,560 this is 0.344 acre, a little over a third of an acre. The area calculator handles the multiplication for other shapes.
Example 3: how long is the side of a square acre?
If an acre were a square, each side would be the square root of 43,560, which is 208.71 ft. A square 200 ft on a side is 40,000 ft², or 0.918 acre, so a square lot needs about 209 ft per side to reach one acre. NIST's handbook notes that an acre need not be square.
Example 4: acres to hectares
A 40-acre field is 40 × 0.40468564 = 16.19 hectares. Going the other way, 10 hectares is 10 × 2.4710538 = 24.71 acres.
Example 5: acres and square miles
A parcel of 320 acres is half of a square mile, since a square mile is 640 acres. In square feet that is 320 × 43,560 = 13,939,200.
International acre or survey acre?
On the retired US survey foot the acre is 4,046.872609874 m² instead of 4,046.8564224 m², a difference of about 0.0004%; in square feet, an acre is 43,560 on both. See international vs survey foot.
Quick ways to estimate: square feet in an acre
- Acres to square feet: multiply by 40,000 and add 9% (3 acres: 120,000 + 10,800 = 130,800, against the exact 130,680).
- Square feet to acres: divide by 40,000 and subtract about 8% (20,000 ft²: 0.5 − 0.04 = 0.46, against the exact 0.459).
- Check: an acre is a bit less than 44,000 ft² and roughly 4,000 m².
For other conversions with imperial and metric units, see the metric vs imperial guide and the unit converters.
International foot vs US survey foot
All the figures in this guide use the international foot of exactly 0.3048 m. Until the end of 2022, US land surveys sometimes used a slightly different foot, the US survey foot, defined as 0.3048006 m (NIST's approximation).
- Mile: a survey mile, still 5,280 survey feet, measured 1,609.347 m against 1,609.344 m for the statute mile, a difference of about 3 mm per mile.
- Acre: NIST's revised factors list the acre as 4,046.8564224 m² on the international foot and 4,046.872609874 m² on the survey foot, a difference of about 0.0004%. In square feet, an acre is 43,560 on both.
NIST and the National Geodetic Survey set 31 December 2022 as the last day the US survey foot should be used; from 1 January 2023 it is treated as obsolete and the international foot applies, other than for historic and legacy data. NIST directs that the survey foot be avoided except for those uses, so the international values apply in everyday work. Everyday conversions never need the survey values, since a 3 mm gap per mile is invisible in a walk or a drive.