Treasury calculator

Bills, notes and bonds, and Series I and EE savings bonds, on Treasury's own conventions rather than an approximation of them.

Value a Series EE bond

Amount paid is half the face for a paper EE bond, $12.50 bought a $25 bond.

Why these numbers may not match your spreadsheet

  • Settlement is T+1, against the bond calendar. A Friday trade settles Monday, unless the Monday is a holiday, in which case it settles Tuesday. Every result states the settlement date it actually used, because discounting to the wrong day biases the short end by tens of basis points.
  • A bill's three rates are not interchangeable. The discount rate is ACT/360 against face, which is how Treasury quotes it. The investment rate is ACT/365 against price, and is the one comparable with a note's yield. Whether the year is 365 or 366 is keyed off the issue date, not the calendar year.
  • The final coupon period is simple interest, not compound. And the two diverge as the stub shortens rather than converging, the gap tends to (y/2)², about 6.25 bp at a 5% yield, and reaches 5.7 bp a day from redemption. If a result is flagged as a final period and disagrees with a compound calculation, that is why.

Index levels before September 30, 2026 are back-tested. They were computed after the fact by applying the rules to historical data, which benefits from hindsight in the choice of rules, and an index cannot be invested in directly. Methodology v1.0 takes effect at that rebalance, when levels begin to be struck on the day; the rulebook is identical either way, and the version is published on every row.

A fitted curve is a fit, not a quote. Daily error averages 3.8 basis points across the history and reaches about 20 on the worst days, in December 2008, when the market was genuinely hard to fit one smooth curve to. Every curve page publishes its own fit error rather than burying it.

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Safe Rate™, Safe Rate Indices™ and the Safe Rate US Treasury Index™ are trademarks of Safe Rate, claimed through use in commerce and not registered. Third-party marks are the property of their owners, which are not affiliated with and do not endorse this data.

Curves are fitted from public Treasury data and carry fit error; figures are not a record of trading, and an index cannot be invested in directly. No claim of compliance with the IOSCO Principles for Financial Benchmarks is made or implied. Not investment advice, not an offer, and not a recommendation to buy or sell any security.