Torr to atm Converter

How to convert torr to standard atmospheres

1 torr = 0.0013157895 standard atmospheres. To convert torr to standard atmospheres, divide by 760 (or multiply by 0.0013157895). A torr is exactly 1/760 of a standard atmosphere, about 133.322 pascals. One standard atmosphere is exactly 101,325 pascals (101.325 kPa), roughly the air pressure at sea level.

Worked examples

• 380 torr = 0.5 atm (380 ÷ 760)
• 760 torr = 1 atm (760 ÷ 760)
• 1,000 torr = 1.31579 atm (1,000 ÷ 760)

Where this conversion comes up

Torr are used for vacuum gauges, gas-law problems and lab equipment; standard atmospheres for chemistry, gas laws and diving. Gas-law problems in chemistry often give pressure in torr and ask for atmospheres, because R = 0.08206 L·atm/(mol·K) needs atm. One atmosphere is exactly 760 torr, so 380 torr is 0.5 atm. Vacuum gauges also read in torr: a rough vacuum of 1 torr is about 0.0013 atm.

Quick estimate

Divide by 760. Half of 760 is 0.5 atm, a quarter (190 torr) is 0.25 atm.

Common mistakes

• Multiplying instead of dividing. A standard atmosphere is larger than a torr, so the number of standard atmospheres must come out smaller: 380 torr = 0.5 atm.
• Rounding too early. Keep the full factor until the last step; rounding 0.00132 to 0.0013 first puts large values noticeably off.

Related pressure converters: bar to psi, psi to bar, kpa to psi, psi to kpa, mpa to psi, psi to mpa.