Series I Savings Bonds

Use I bonds to

save in a low-risk product that helps protect your savings from inflation
supplement your retirement income
give as a gift
pay for education

What is an I bond?	A savings bond that earns interest based on combining a fixed rate and an inflation rate. Comparing I Bonds to EE Bonds Comparing I Bonds to Treasury Inflation-Protected Securities (TIPS)
What interest does an I bond earn?	A combination of a fixed rate that stays the same for the life of the bond and an inflation rate that is set twice a year. How do I bonds earn interest?
Is it taxable?	Federal income tax: Yes State and local income tax: No Tax Considerations for I bonds Using the money for higher education may keep you from paying federal income tax on your interest. See "Education Planning."
Paper or electronic?	Both. (You can buy a paper I bond only when filing a federal income tax return.)
Minimum purchase	Electronic: $25 Paper: $50
Maximum purchase	Electronic: $10,000, total, each calendar year Paper: $5,000, total, each calendar year
Available bonds	Electronic: Any amount, to the penny, from $25 to $10,000. Paper: $50, $100, $200, $500, $1,000
How long must I keep an I bond?	I bonds earn interest for 30 years unless you cash them first. You can cash them after one year. But if you cash them before five years, you lose the previous three months of interest. (For example, if you cash an I bond after 18 months, you get the first 15 months of interest.)
How do I buy an I bond?	Electronic: Online in TreasuryDirect (including through payroll direct deposit) Paper: By mail when you file your federal tax return

How do I bonds earn interest?

Interest on an I bond is a combination of two rates:

A fixed rate of return which remains the same throughout the life of the I bond

and
A variable inflation rate which we calculate twice a year, based on changes in the nonseasonally adjusted Consumer Price Index for all Urban Consumers (CPI-U) for all items, including food and energy (CPI-U for March compared with the CPI-U for September of the same year, and then CPI-U for September compared with the CPI-U for March of the following year).

Interest is earned on the bond every month. The interest is compounded semiannually: twice a year, the interest the bond earned in the previous six months is added to the bond's principal value; then, interest for the next six months is calculated using this adjusted principal.

The interest and principal are paid to you when you cash the bond.

For more details: Calculating Interest Rates on I bonds

To see specifics for your I bond: Savings Bond Calculator