About

About ibondrate

A free, open calculator that turns one I bond issue date into a clear redemption-timing plan.

US Series I savings bonds have rules that make timing matter: you can't cash one for 12 months, you forfeit the last 3 months of interest if you redeem before 5 years, and your rate resets every 6 months on the bond's own anniversary. Most pages explain this in prose. ibondrate does the arithmetic for your bond.

ibondrate turns one input — your I bond's issue month and what you paid — into the timing answers that matter: when it unlocks, when the early-withdrawal penalty ends, what rate it earns now and next, an estimate of its value, and the specific month to cash out so the unavoidable 3-month penalty lands on the cheapest months. It uses the U.S. Treasury fixed-rate and semiannual-inflation tables (cross-checked against TreasuryDirect announcements) and the published composite-rate formula. Dollar amounts are estimates for planning; rates and dates are exact. It is informational only — not financial advice — and runs entirely in your browser.

It reads the U.S. Treasury fixed-rate and semiannual-inflation tables (from the Fiscal Data dataset, cross-checked against TreasuryDirect's rate announcements), applies the published composite-rate formula for each of the bond's 6-month periods, and shows the current and next rate, an estimated value, the 3-month penalty, every key date, and the specific month to redeem so the penalty falls on the lowest-rate months. Because it is a static page, your inputs stay in your browser.

Not affiliated with the U.S. Department of the Treasury or TreasuryDirect. This is an informational tool, not financial advice; for the official value to the penny and for any decision about your money, use TreasuryDirect and, if needed, a licensed professional. Run the calculator →