Standard Tier Module

Patent Term & Maintenance-Fee Calculator

Compute a U.S. patent's expiration and maintenance-fee windows by exact, auditable date math.

See it run - a worked example, 100% in this browser tab

The problem

Missing a patent's 3.5, 7.5, or 11.5-year maintenance window lets a patent lapse, and term dates shift with filing type, PTA, and PTE, so a hand-counted date is easy to get wrong.

The local-first solution

A deterministic, client-side calculator derives expiration and every maintenance window by exact UTC-date arithmetic, citing 35 U.S.C. 154/41 and 37 CFR 1.20, with nothing uploaded.

What it does

Utility/plant term: 20 years from earliest non-provisional or PCT filing (154(a)(2))

Adds any Patent Term Adjustment and Patent Term Extension days you supply (154(b), 156)

Design term: 15 years from grant for filings on/after 2015-05-13, else 14 (173)

Maintenance windows at 3.5, 7.5, 11.5 years post-grant with 6-month grace (37 CFR 1.20)

Returns the window dates, not stale hardcoded fee amounts

Exact UTC calendar arithmetic, no drift

Honest scope

Dates only. It does not account for a terminal disclaimer, a later-expiring related patent, continuation priority nuances, PTA recalculation, or abandonment/revival; PTA and PTE day counts come from the USPTO record and are not computed here. Not legal advice.

Authorities cited

35 U.S.C. 154(a)(2) - Utility/plant patent term: 20 years from the earliest U.S. non-provisional (or PCT) filing date.
35 U.S.C. 154(b) - Patent Term Adjustment (PTA) for USPTO delay.
35 U.S.C. 156 - Patent Term Extension (PTE) for regulatory review.
35 U.S.C. 173 - Design patent term: 15 years from grant (filed on/after May 13, 2015; 14 years if before).
35 U.S.C. 41(b) / 37 CFR 1.20 - Maintenance fees due at 3.5, 7.5, and 11.5 years, each with a 6-month grace period (with surcharge).

Compute the term and windows

Run the patent dates in your browser and dock the cited maintenance schedule into a Sandbox set or a Worklog case. Nothing is uploaded to anyone's cloud.

Try it live inside GDBS Open a free Standard account

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