Ee Calculator
EE stands for Series EE, the U.S. savings bond sold by the Treasury at face value since May 2005. This EE calculator projects what a savings bond purchase could grow to at a fixed annual rate you choose: it shows the value at the end of your holding period, the interest earned, and the value at the two marks that matter most for savings bonds, 20 years and 30 years. It covers Series I purchases too, with one honest limit explained below: it projects growth at the single rate you enter, and it is not the official redemption value of a bond you already own.
Quick Answer
A $1,000 Series EE purchase growing at a steady 2.5% a year is worth $1,638.62 after 20 years, of which $638.62 is interest, and $2,097.57 after 30 years. One catch the projection cannot show: a real EE bond is guaranteed by the Treasury to be worth at least $2,000 at the 20-year mark, so at low fixed rates the official value at year 20 beats this flat-rate projection.
Key takeaways
- EE means Series EE savings bonds. The EE name is a series label from the Treasury, not an engineering term.
- This tool grows your purchase at one annual rate you enter. It does not look up your bond, its issue-date rate, or its accrued interest.
- Only three inputs drive the maths: the purchase amount, the annual rate, and the holding period. Nothing else is asked for, because nothing else changes the projection.
- For the exact value of a paper bond you already own, the TreasuryDirect savings bond calculator is the official source. This page is for planning a purchase or testing a rate.
- Quick Answer
- How to use the EE calculator, field by field
- The formula: simple annual compounding, stated plainly
- Worked example: $1,000 of Series EE at 2.5% for 20 years
- What the rate does: $1,000 across five rates
- Series EE vs Series I: the differences this projection cannot show
- What competing calculators miss
- When to cash in: the three dates that change the answer
- Frequently asked questions
- Add This Calculator to Your Website
How to use the EE calculator, field by field
Enter what you paid or plan to pay, set the rate and holding period, then click Calculate. The results stay hidden until you do.
- Purchase amount: electronic savings bonds are bought at face value, from $25 up to $10,000 per series, per person, per calendar year, according to the TreasuryDirect savings bond FAQs.
- Annual interest rate: the fixed rate to project at. It defaults to 2.5%, the fixed rate the Treasury announced for EE bonds bought from November 2025 through April 2026. An older EE bond carries the fixed rate from its own issue period, so enter that rate if you know it.
- Holding period: how long the money stays in, in years. Half years are accepted, so 7.5 works.
The four results are the value at the end of your holding period, the interest inside that value, and the values at 20 and 30 years at the same rate. Those two extra lines exist because savings bonds have a 20-year promise and a 30-year finish line, and savers comparing this with a high-yield savings calculator usually want the long view, not just next year.
The formula: simple annual compounding, stated plainly
The tool applies one compound growth formula to your purchase amount, the same growth engine behind a compound interest doubling time calculator, just pointed at a savings bond.
Interest earned = Value − Purchase amount
Value at 20 years = Purchase amount × (1 + Annual rate) ^ 20
Value at 30 years = Purchase amount × (1 + Annual rate) ^ 30
Three ways the real Treasury maths differs from this projection, so you know exactly what you are looking at:
- Compounding frequency: real EE and I bonds add interest monthly and compound semiannually, as the TreasuryDirect glossary for savings bonds describes. This tool compounds once a year, which slightly understates growth at the same stated rate.
- The 20-year doubling guarantee: Treasury guarantees an EE bond held for 20 years will be worth at least double its purchase price, topping the value up in a one-time adjustment if interest alone falls short. At 2.5% compounded annually, $1,000 reaches only $1,638.62 in 20 years, so the guarantee is worth real money at today’s fixed rates. A rate of about 3.53% is what annual compounding needs to double money in 20 years on its own.
- Series I rates move: an I bond earns a composite rate made of a fixed part and an inflation part that resets every six months. One flat rate cannot track that. Use the I setting here only as a what-if at an assumed average rate.
Worked example: $1,000 of Series EE at 2.5% for 20 years
The calculator loads with this example already filled in: a $1,000 Series EE purchase at a 2.5% annual rate, held for 20 years.
| Result | Amount | How it is built |
|---|---|---|
| Current value (20 years) | $1,638.62 | $1,000 × 1.025 ^ 20 |
| Total interest earned | $638.62 | $1,638.62 − $1,000 |
| Value at 20 years | $1,638.62 | Same line, because the holding period is 20 years |
| Value at 30 years | $2,097.57 | $1,000 × 1.025 ^ 30 |
Where the 20-year value comes from:
Read that against the guarantee: the Treasury would pay at least $2,000 for this bond at year 20, not $1,638.62. The projection is the honest floor of what the stated rate alone produces; the guarantee sits on top of it for EE bonds. If you are setting money aside month by month instead of buying one bond, a daily savings calculator models that habit better than a single purchase does.
What the rate does: $1,000 across five rates
Small rate differences look minor in year one and large by year 20, which is the whole reason the holding period matters more than the headline rate.
| Annual rate | Value at 20 years | Value at 30 years | Note |
|---|---|---|---|
| 1.00% | $1,220.19 | $1,347.85 | EE guarantee tops year 20 up to $2,000 |
| 2.00% | $1,485.95 | $1,811.36 | EE guarantee tops year 20 up to $2,000 |
| 2.50% | $1,638.62 | $2,097.57 | Current EE fixed rate (Nov 2025 to Apr 2026 issues) |
| 3.00% | $1,806.11 | $2,427.26 | Still short of doubling by year 20 |
| 3.53% | $2,001.36 | $2,831.30 | About the rate where growth alone doubles the money |
Series EE vs Series I: the differences this projection cannot show
Both series share the same purchase limits, the same 12-month lock, the same early-redemption penalty, and the same 30-year life. They earn interest in completely different ways, which is why a single-rate projection fits one of them far better than the other.
| Feature | Series EE | Series I |
|---|---|---|
| How the rate works | One fixed rate set at purchase, kept for the life of the bond | Composite rate: a fixed part plus an inflation part that resets every 6 months |
| 20-year guarantee | Yes: guaranteed to at least double at 20 years | No guarantee of any particular value |
| Fits a flat-rate projection? | Well, apart from semiannual compounding and the guarantee | Only as a rough average-rate scenario |
| Best known for | Predictable long-term growth and the doubling promise | Keeping pace with inflation |
Tax treatment is shared: interest is subject to federal income tax but exempt from state and local tax, and you can defer the federal tax until you cash the bond or it matures, per the TreasuryDirect FAQs. The redemption rules for definitive (paper) bonds, including the three-month penalty on bonds redeemed before five years, are set out in the federal regulation at 31 CFR 351.51 on bond values.
What competing calculators miss
The official TreasuryDirect tool is exact, and every other tool in this space, this one included, is a step below it for valuing a bond you already hold. Here is the honest lay of the land.
- TreasuryDirect prices real bonds, but only paper ones, and only at real rates: it needs a series, a denomination, and an issue date, and it returns the true redemption value, the current rate, the next accrual date, and the maturity date. It cannot answer planning questions like “what if I buy $5,000 at today’s fixed rate and hold 12 years?” That what-if gap is what this tool fills.
- Generic compound interest tools know nothing about savings bonds: no doubling guarantee, no 30-year stop, no 12-month lock, no three-month early penalty. Their output looks identical for a bond, a savings account, and a stock fund, which hides the rules that actually drive the cash-in decision.
- Some EE maturity tools present assumed-rate tables as bond values: round-number growth tables look official but rest on a guessed rate. This page labels every figure as a projection at the rate you entered, and shows the formula so you can re-run it with your bond’s actual fixed rate.
- Few tools admit the limits of a projection: this page asks only for the amount, the rate, and the holding period, because those are the only numbers its formula uses, and it labels every figure a projection at the rate you entered.
When to cash in: the three dates that change the answer
The projection assumes you hold for the full period you entered. Real cash-in decisions hinge on three dates.
- Before 12 months: you cannot cash in at all. Savings bonds are locked for the first year, emergency access aside.
- Between 1 and 5 years: you can cash in, but you give up the last three months of interest. On a small, short-held bond that penalty can erase a large share of the growth.
- At 20 years (EE only): the doubling adjustment lands. Cashing an EE bond at 19 years and 11 months instead of 20 years can mean leaving the entire top-up behind, which at a 2.5% fixed rate is the difference between $1,638.62 and at least $2,000 on a $1,000 purchase.
- At 30 years: interest stops for good. A bond held past final maturity earns nothing while inflation keeps working, so matured bonds sitting in a drawer should be cashed and put back to work.
Frequently asked questions
EE is the series name of a U.S. savings bond: Series EE. It has nothing to do with electrical engineering. Series EE bonds are sold by the U.S. Treasury at face value, earn a fixed rate of interest set when you buy, and are guaranteed to be worth at least double the purchase price if you hold them for 20 years.
No. This calculator projects growth at the single annual rate you enter, compounded once a year. It does not know your bond’s issue date rate history, its accrued interest, or the early-redemption penalty, so it cannot give an official redemption value. For the exact value of a paper bond, use the TreasuryDirect savings bond calculator; for electronic bonds, the value shows in your TreasuryDirect account.
Three numbers only: the purchase amount, the annual interest rate, and the holding period in years. Enter the amount you paid or plan to pay, the fixed annual rate to project at, and how long you will hold the bond, and the calculator compounds the amount at that rate for that period, and for the 20-year and 30-year marks. A real bond’s official value does depend on its series and issue date, which is exactly why official values come from TreasuryDirect.
Yes. The Treasury guarantees that an EE bond held for 20 years will be worth at least double its purchase price. If the fixed rate alone has not doubled it by then, the Treasury makes a one-time adjustment to close the gap. At a 2.5% rate compounded annually, $1,000 grows to $1,638.62 in 20 years, so the guarantee adds at least $361.38 on that purchase. Series I bonds carry no such guarantee.
Enter the fixed rate your bond was issued with. EE bonds keep the fixed rate announced for their six-month issue window: for example, bonds bought from November 2025 through April 2026 carry a 2.50% fixed rate, which is why the calculator loads with 2.5%. Older bonds carry different fixed rates, and EE bonds bought before May 2005 used other rate rules entirely, so check your bond’s issue period on TreasuryDirect before projecting it.
You cannot cash a savings bond in its first 12 months. If you cash in before the bond is 5 years old, you lose the last three months of interest. After 5 years there is no penalty. Both EE and I bonds stop earning interest at 30 years, so there is no benefit to holding one past final maturity.
Savings bond interest is subject to federal income tax but is exempt from state and local income tax. You can defer the federal tax until you cash the bond, it matures, or you reissue it, and under set conditions the interest can be excluded from federal tax when used for qualified higher education expenses. This calculator shows pre-tax values only.
You can run a rough what-if, but treat it as a scenario, not a forecast. An I bond earns a composite rate that combines a fixed rate with an inflation adjustment reset every six months, so no single rate you enter will track a real I bond. Enter an average rate you want to test, and remember the result also ignores the semiannual compounding the Treasury actually uses.
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References
- U.S. Department of the Treasury, TreasuryDirect. Savings Bond Calculator. Accessed October 21, 2026.
- U.S. Department of the Treasury, TreasuryDirect. FAQs about Savings Bonds. Accessed October 21, 2026.
- U.S. Department of the Treasury, TreasuryDirect. Glossary for Savings Bonds Terms. Accessed October 21, 2026.
- U.S. Department of the Treasury, TreasuryDirect. Savings Bond Calculator Help. Accessed October 21, 2026.
- Legal Information Institute, Cornell Law School. 31 CFR 351.51: How can I find out what my definitive Series EE savings bonds are worth? Accessed October 21, 2026.