EE bonds bought now have a fixed rate known at purchase that stays the same for at least the first 20 years and may change for the last 10 of their 30 years. Treasury guarantees that a new EE bond is worth double its purchase price at 20 years. Like I bonds, they are bought electronically through TreasuryDirect, up to $10,000 per Social Security Number per calendar year, and can be cashed after 12 months.
Formula
The doubling guarantee implies a minimum annual return over 20 years of:
2^(1/20) − 1 ≈ 3.53% (annual compounding)
If the stated fixed rate would not double the bond by year 20, Treasury makes up the difference at that point.
Example
EE bonds bought from November 1, 2026 to April 30, 2027 earn 2.90%. $1,000 compounding semiannually at 2.90% for 20 years would reach 1,000 × 1.0145^40 = $1,778.62, so the guarantee lifts it to $2,000. Cashed after 10 years, the same bond would be worth 1,000 × 1.0145^20 = $1,333.65, because the guarantee applies only at 20 years.
Compare it with the inflation-linked Series I savings bond in how do I bonds work, or value a bond with the savings bond calculator.