A US utility patent lasts twenty years from its earliest non-provisional filing date. A design patent lasts fifteen years from grant. Those are the statutory answers, and neither is what most patent owners actually experience.
The term is conditional. A utility patent requires three maintenance fee payments to reach the end of its twenty years, and most owners stop paying long before that. So when people ask how long does a patent last, the honest answer is not twenty years — it is that a patent lasts exactly as long as somebody keeps deciding it is worth paying for.
The statutory term
| Patent type | Term | Runs from | Maintenance fees |
|---|---|---|---|
| Utility | 20 years | Earliest non-provisional filing | Three, at 3.5 / 7.5 / 11.5 years |
| Design (filed on or after 13 May 2015) | 15 years | Grant | None |
| Design (filed before 13 May 2015) | 14 years | Grant | None |
| Plant | 20 years | Filing | None |
Two different clocks run on the same patent, and confusing them is the most common error in this area.
The term clock runs from filing — twenty years from the earliest non-provisional application in the priority chain, under 35 U.S.C. 154. This is the clock that decides when the patent expires.
The fee clock runs from grant — maintenance fees at 3.5, 7.5 and 11.5 years after the patent issues, under 35 U.S.C. 41. This is the clock that decides whether it survives to get there.
A patent filed in 2015 and granted in 2019 expires in 2035, but its fees are due in 2022, 2026 and 2030. Owners who diarise from the wrong date miss the window entirely.
A provisional application does not start the term clock. That is the point of it. A provisional gives twelve months of priority without consuming any of the twenty years, which is why filing one first is standard practice even though it never becomes a patent itself and is never examined. The clock starts when the non-provisional is filed.
Foreign priority behaves the same way. A US application claiming priority to an earlier foreign filing under the Paris Convention gets the benefit of that date for prior art purposes, but the twenty years still run from the US non-provisional filing, not the foreign one.
How long a patent is good for after grant
Because the clock starts at filing, enforceable life is always shorter than twenty years, and the gap is the examination period.
USPTO pendency, FY2024: first office action averaged 19.9 months; total pendency averaged 26.3 months, rising to around 30 months where a Request for Continued Examination was filed.
| Time to grant | Enforceable years remaining |
|---|---|
| 2 years | ~18 |
| 3 years | ~17 |
| 4 years | ~16 |
| 5 years | ~15 |
A patent granted today typically has around seventeen years left, and that is the number to plan around — not the twenty printed in the statute.
Pendency varies substantially by technology centre. Software and business-method applications routinely run longer than mechanical ones, partly because of subject-matter eligibility rejections under §101 that require multiple rounds of response. Two patents filed the same day in different fields can end up with materially different enforceable lives, and the applicant has limited control over which.
Track One prioritised examination compresses this. For an additional fee the USPTO targets final disposition within twelve months, which can preserve two or three years of enforceable term. On a patent expected to be commercially important that trade is usually worth making, and on a speculative filing it usually is not.
How long can a patent last in practice, then? For a utility patent that survives all three fees, seventeen years of enforceable life is typical, twenty is the ceiling, and anything beyond that requires Patent Term Adjustment or Extension.
What actually happens to patents
Computed from every maintenance fee event the USPTO has recorded — 27,273,654 rows covering 8,262,336 US utility patents granted since 1981.
| Grant year | Patents granted | Survived 3.5 yr | Survived 7.5 yr | Reached full term |
|---|---|---|---|---|
| 2000 | 157,420 | 85.7% | 68.7% | 51.1% |
| 2005 | 143,784 | 87.5% | 69.3% | 46.0% |
| 2010 | 219,522 | 86.6% | 65.9% | 43.1% |
| 2012 | 253,064 | 85.7% | 64.6% | 42.1% |
| 2014 | 300,626 | 85.8% | 64.6% | 41.4% |
Only 41.4% of patents granted in 2014 reached full term. The other 58.6% expired early — not because anything went wrong legally, but because an owner looked at a fee and decided the patent was not worth it.
Attrition is not evenly distributed across the three stages:
| Stage | Cumulative survival | Lost at this stage |
|---|---|---|
| At grant | 100% | — |
| Past first fee | 85.8% | 14.2% |
| Past second fee | 64.6% | 21.2 points |
| Past third fee | 41.4% | 23.2 points |
The largest single loss is at the third fee, where 23.2 percentage points of the original cohort drop out. That is the $8,280 payment doing its work — the schedule escalates deliberately so that patents nobody values are released into the public domain rather than held defensively for two decades.
The rate is falling. Patents granted in 2000 reached full term 51.1% of the time; those granted in 2014 managed 41.4%. The decline tracks the fee schedule almost exactly. The 11.5-year fee for a large entity has gone from $3,100 in 2001 to $8,280 as of January 2025 — a 167% increase against roughly 80% cumulative inflation over the same period.
Full figures by grant year are on the Ipiry Patent Survival Curve.
The three maintenance fees
Each fee has a window, not a date. The window opens six months before the anniversary and closes on it. Miss it and a six-month grace period follows, with a surcharge. Miss the grace period and the patent expires permanently.
| Fee | Window closes | Large entity | Small entity | Micro entity |
|---|---|---|---|---|
| First | 3.5 years after grant | $2,150 | $860 | $430 |
| Second | 7.5 years after grant | $4,040 | $1,616 | $808 |
| Third | 11.5 years after grant | $8,280 | $3,312 | $1,656 |
| Total | $14,470 | $5,788 | $2,894 |
Amounts effective January 2025. Fees are revised roughly every one to three years.
You cannot prepay. A fee can only be paid during its own window, which means the obligation recurs three times and each occasion is a fresh decision. There is no way to settle a patent's maintenance cost up front and stop thinking about it.
What the USPTO reminder actually is
The Office sends a maintenance fee reminder to the correspondence address of record, usually a few months into the window. It is a courtesy, not a requirement. The statute does not condition expiry on the reminder being received, and the patent lapses whether or not anyone read it.
This matters because the correspondence address is frequently stale. It is set at filing, often to a law firm that finished its engagement years earlier. A patent whose prosecuting attorney has retired, or whose owner has moved offices twice since grant, will still generate a reminder — sent somewhere nobody is reading.
The failure mode is not carelessness. It is address drift, and it accounts for a meaningful share of accidental abandonments.
Checking status in Patent Center
To confirm where a specific patent stands, look it up in USPTO Patent Center and compare recorded maintenance fee payments against the grant date.
What you are looking for: a payment recorded at each stage the patent has reached. If a window and its grace period have both closed with no payment recorded, the patent has expired.
What to be careful about: the record can lag actual payment by a short period, so a very recent payment may not show. And commercial patent databases update on their own schedules — a patent shown as active in a third-party tool may have lapsed weeks earlier. For anything that matters, check the USPTO record directly.
Entity status, and why it needs rechecking
Entity status is certified at each payment rather than fixed at grant, and the difference across a patent's life is substantial — $14,470 against $2,894.
Small entity status under 37 CFR 1.27 pays 40%. It requires fewer than 500 employees including affiliates, and no assignment, licence or obligation to assign rights to an entity that would not itself qualify.
Micro entity status under 37 CFR 1.29 pays 20%. It requires small entity status, plus being named as inventor on fewer than five prior US non-provisional applications, plus gross income in the preceding year below approximately $251,190 — three times median household income, adjusted periodically.
The trap is claiming a status you have lost. A startup that qualified as a micro entity at filing may have crossed the income threshold or the application count by the second fee, eight years later. Paying at the wrong rate is a fee deficiency, and correcting it afterwards under 37 CFR 1.28 requires a further petition and payment of the difference.
Check before every payment, not once at the start. Twelve years is enough time for circumstances to change twice.
A worked example: the whole life of one patent
A utility patent filed 12 March 2015, granted 18 June 2019, small entity throughout.
| Event | Date | Cost | Notes |
|---|---|---|---|
| Earliest filing | 12 Mar 2015 | — | Term clock starts |
| Grant | 18 Jun 2019 | Issue fee | Fee clock starts. ~15.8 years enforceable |
| First window opens | 18 Jun 2022 | — | Six months to act |
| First fee due | 18 Dec 2022 | $860 | Grace to 18 Jun 2023 |
| Second fee due | 18 Dec 2026 | $1,616 | Grace to 18 Jun 2027 |
| Third fee due | 18 Dec 2030 | $3,312 | Grace to 18 Jun 2031 |
| Term expires | 12 Mar 2035 | — | 20 years from filing |
Total USPTO maintenance cost across the life: $5,788. Note what the third fee buys — four years and three months of protection, from December 2030 to March 2035, with nothing further to pay. On a patent generating revenue that is straightforward. On one that is not, $3,312 for a four-year tail is exactly the decision the schedule is designed to force.
The version where the second fee is missed
The owner changes office in 2026, the reminder goes to the old address, and nobody notices until 2028.
| Event | Date | Outcome |
|---|---|---|
| Second fee due | 18 Dec 2026 | Not paid |
| Grace period ends | 18 Jun 2027 | Patent expires |
| Competitor launches | Sep 2027 | Began during the lapse |
| Discovery | Mar 2028 | Nine months after expiry |
| Petition to revive | 2028 | $1,616 + petition fee, discretionary |
The patent can probably be revived. It cannot be made whole. Under 37 CFR 1.378 the Office may accept a delayed payment where the entire delay was unintentional, which forgetting generally satisfies. But the competitor who started while it was lapsed may be permitted to continue under intervening rights — and that competitor is precisely the party the patent existed to exclude.
The cost of the miss is not $1,616. It is exclusivity against the one company that was paying attention.
The version where the patent is sold instead
Same patent, but at the third fee in 2030 the owner concludes the technology has moved on and will not pay $3,312.
| Path | Cash | Fee obligation | Outcome |
|---|---|---|---|
| Let it lapse | $0 | Ends | Public domain, permanently |
| Sell before the window closes | Sale proceeds | Transfers to buyer | Owned by someone who values it |
Both paths end the fee obligation. The difference is whether anything comes back. A patent sold in November 2030 is worth whatever a buyer pays; the same patent in July 2031 is worth nothing at all, because there is no longer an exclusive right to transfer.
The conditional rate: what happens to patents like yours
The overall 41.4% understates what happens to any particular patent, because it averages owners who abandoned at the first fee with owners still paying at the third.
| Position | Share who pay the next fee |
|---|---|
| Paid the first fee | 74.3% go on to pay the second |
| Paid the first two | 63.0% go on to pay the third |
Paying a maintenance fee is a revealed valuation. An owner who has paid twice has twice concluded the patent is worth more than the fee. That is why 63% of them pay a third time, against an overall full-term rate of 41.4%.
So the question at a fee deadline is not what most patents do. Most patents belong to owners who never had a commercial use for them. The relevant question is what your patent is worth relative to the fee in front of you.
How the term gets longer
Two mechanisms extend a utility patent beyond twenty years. They are not interchangeable and they are frequently confused.
Patent Term Adjustment
Compensates for USPTO delay. The Office guarantees a first action within fourteen months of filing and issuance within three years. Days beyond those guarantees are added to the term under 35 U.S.C. 154(b), less any days of applicant delay.
PTA is calculated automatically at issue and printed on the face of the patent, usually near the filing date. Most owners never look at it.
It can be disputed within two months of grant. The calculation is mechanical and errors happen, particularly where prosecution involved appeals or multiple RCEs. On a patent where prosecution ran long, checking the figure is worth the hour it takes.
Applicant delay reduces it day for day. Every extension of time taken on an office action response counts against you. Taking the full three-month extension routinely is a choice that costs term, and on a long prosecution it can eliminate the adjustment entirely — a patent that took four years to grant because the applicant was slow gets nothing.
Patent Term Extension
Compensates for regulatory review rather than examination delay. Under 35 U.S.C. 156, one patent per FDA-approved product may recover up to five years of the time consumed by clinical trials and agency review, capped so that effective patent life after approval does not exceed fourteen years.
It must be applied for within sixty days of approval. Not automatic, and the deadline is unforgiving.
Only one patent per product qualifies, so a company with several patents covering the same drug must choose which to extend — normally the one with the broadest claims or the longest remaining term.
PTA and PTE stack. A pharmaceutical patent can carry both, which is why some drug patents run well past twenty years from filing, and why how long do drug patents last has a different answer from every other technology field.
FDA exclusivity is separate again. New chemical entity exclusivity, orphan drug exclusivity and paediatric exclusivity are regulatory protections that run on their own timetable and can outlast the patent entirely. A drug can be unpatented and still not face generic competition.
How the term gets shorter
Unpaid maintenance fees. The dominant cause, accounting for the entire 58.6%.
Terminal disclaimer. Filed to overcome an obviousness-type double patenting rejection, a terminal disclaimer surrenders any term extending beyond an earlier related patent. It is a deliberate trade — a shorter term in exchange for allowance — and it is permanent and irrevocable.
On a family with several continuations this compounds. A continuation filed four years after its parent might expect four extra years of term from its later filing date, but a terminal disclaimer aligning it to the parent removes that entirely. Families built through aggressive continuation practice frequently have much less aggregate term than their filing dates suggest.
Applicant delay, as covered above, eats PTA.
Statutory disclaimer. Rare, but a patentee can disclaim claims or the whole patent under 35 U.S.C. 253, occasionally as a litigation tactic.
What happens when a patent expires
The exclusive right ends completely. Anyone may make, use, sell, offer for sale or import the claimed invention without permission, royalty or notice. The invention is in the public domain.
Past infringement survives. A claim that accrued while the patent was in force can still be brought, subject to the six-year damages limitation in 35 U.S.C. 286. Expiry ends future infringement, not past liability.
Post-expiry royalties are unenforceable. A licence requiring payment for use after expiry is unenforceable as to that period, under Brulotte v. Thys and reaffirmed in Kimble v. Marvel. Licence agreements that do not address expiry can leave a licensor collecting nothing.
The disclosure stays public and remains prior art against later applications. Expiry removes the right to exclude, not the teaching.
The decision you are actually making
A maintenance fee is not an administrative cost. It is a purchase. You are buying four more years of exclusivity for a stated price, and the question is whether four years is worth $2,150, or $4,040, or $8,280.
That depends on things a fee schedule cannot tell you.
Is anyone practising the invention? The single largest factor, and one most owners never establish properly. It means looking at what competitors actually ship — product literature, specifications, teardowns, their own patent filings — and comparing that against your claims element by element. A patent nobody infringes has option value rather than enforcement value, and option value declines as the term runs down. A patent with four years left and no identified infringer is worth considerably less than the same patent with twelve.
Is the technology still current? A patent covering a superseded approach, arriving at its 11.5-year fee, is usually one to release. Eleven years is a long time in most fields, and the escalating schedule exists precisely to force this reassessment rather than let patents accumulate by inertia.
Is there a buyer? A patent with commercial relevance is worth more sold than lapsed, and the fee deadline is a forcing function. The buyer inherits the maintenance obligation, which means a patent you will not pay for can be an asset to someone who will.
What does it appraise at? Which is the question the fee decision reduces to, and the reason patent valuation usually happens at a renewal deadline rather than at any other point in a patent's life.
The asymmetry is stark. A patent sold before the window closes is worth something. The same patent a month after lapse is worth nothing. Both outcomes end the fee obligation; only one pays you for it.
Before your next fee deadline
- Check the exact due date from the grant date, not the filing date, and note both the window close and the grace period end.
- Confirm the correspondence address of record is somewhere you actually read, because the reminder goes there and nowhere else.
- Recheck entity status — it may have changed in either direction since the last payment, and paying at the wrong rate creates a deficiency.
- Check your PTA on the face of the patent if you never have. On a slow prosecution it may be worth more term than you think.
- Establish whether anyone is practising the invention. That is the difference between an asset and a liability, and it takes research rather than assumption.
- Get a valuation before the window closes, not after. A lapsed patent cannot be sold.
- If you are not going to pay, offer it for sale first. The buyer inherits the fee obligation and you recover something rather than nothing.
- If you do pay, diarise the next window the same day. Missing the second fee after paying the first wastes the first payment entirely.