About & methodology
Every number on this site traces to a U.S. Treasury source. Here is exactly how.
What this site does
Savings Bond Check answers two questions well: what is a given US savings bond worth today, and is it still earning interest? It publishes the U.S. Treasury's official redemption values - the value file behind TreasuryDirect's own calculator - as browsable tables for every series, issue year, issue month, and denomination, plus final-maturity rules, current I bond rates, taxes, cashing, and inheritance paths for Series E, EE, I, and HH bonds and Savings Notes.
What it deliberately does not do
- No invented numbers. Every dollar value is Treasury's published per-$25 redemption value, scaled exactly (face ÷ $25 is a whole number for every denomination). You can cross-check any figure on the official TreasuryDirect Savings Bond Calculator - the two always agree, because they read the same file.
- No investment, tax, or legal advice. Pages describe Treasury's official processes and link to the official source for every claim.
- No predictions - future rates and values appear here only after Treasury publishes them.
Data sources
- Redemption values: the U.S. Treasury Fiscal Data API,
Savings Bonds Value Files dataset
(endpoint
v2/accounting/od/sb_value) - the official redemption value per $25 of face value for every Series E, EE, and I bond and Savings Note, at every redemption month since 1992 (35,936 rows this build, published through November 2026). For bonds under 5 years old the published values already reflect the 3-month early-redemption penalty. - I bond rates:
I Bonds Interest Rates dataset
(endpoint
v1/accounting/od/i_bonds_interest_rates) - the combined rate for every issue-month cohort in every semiannual rate period since September 1998 (9,690 rows this build). Cross-checked at build time against the announced rate on treasurydirect.gov; the build fails if they disagree. - Matured/outstanding totals:
Monthly Statement of the Public Debt, Table III
(endpoint
v1/debt/mspd/mspd_table_3) - matured unredeemed savings securities, monthly since 2001, and outstanding amounts by series. - Bond counts by series:
Savings Bonds: Issues, Redemptions, and
Maturities by Series
(endpoint
v1/accounting/od/savings_bonds_report) - monthly counts of bonds issued, redeemed, outstanding, and matured-unredeemed. - Rules and procedures (maturity periods, series timelines, cashing, inheritance, tax treatment): the relevant TreasuryDirect pages, linked inline wherever a claim is made.
Methodology & integrity checks
Every build re-fetches all four datasets and refuses to publish if any
check fails - the previously published site stays live instead. The checks:
the I bond composite formula
(composite = fixed + 2 × inflation + fixed × inflation, floored
at zero) is verified against every row of the rates dataset; the value file
must cover the build month, contain all four series with their known
issue-year spans, and pass range checks; I bond cohort values must never
decrease month over month; matured Series E values must be frozen; and EE
bonds issued May 2005 or later must show their guaranteed doubling by 20
years. Per-bond "current rate" figures account for each bond's own six-month
reset schedule. Maturity dates are computed from the statutory terms:
30 years for EE and I bonds, 20 for HH, and 30 or 40 years for Series E
depending on issue date.
Update cadence
Redemption values and rates change on Treasury's announcement dates, May 1 and November 1; MSPD figures and bond counts update monthly. The site is rebuilt from the live APIs at least monthly (and around each announcement), and every page footer shows its data-refresh date. All underlying data is US-government public domain; this site's tables are free to cite with a link.
Contact
contact@savingsbondcheck.com - corrections are welcome and applied fast.