Do patents expire?

Yes. Patents expire, all of them, and most expire early. When people ask do patents expire, they usually mean something more specific: whether the end date printed on the patent is the one that matters. Usually it is not.

There are two distinct ways a US patent ends, and they are frequently confused even by people who own patents.

The two ways a patent ends

Term expiry is the one everybody knows about. Twenty years from the earliest non-provisional filing date for a utility patent under 35 U.S.C. 154. Fifteen years from grant for a design patent under 35 U.S.C. 173. These are hard limits and nothing extends them once reached.

Lapse is the one that actually happens. Three maintenance fees fall due at 3.5, 7.5 and 11.5 years after grant. Miss one and the patent expires at the end of a six-month grace period, permanently, with no notice beyond a courtesy reminder sent to whatever address is on file.

The majority of US patents end the second way, not the first. That is the single most useful thing to understand about patent expiry, and it is the opposite of what most people assume.

Can patents expire before their term is up?

Routinely, and by several routes.

Unpaid maintenance fees account for almost all of it. This is not a penalty or a failure — it is the system working as designed. The fees escalate deliberately so that owners who no longer value a patent release it rather than hold it defensively at trivial cost.

Terminal disclaimers shorten the term at the front end. Filed during prosecution to overcome an obviousness-type double patenting rejection, a terminal disclaimer surrenders any term extending beyond an earlier related patent. It is permanent and irrevocable, and on families built through continuation practice it can remove years of expected term.

Applicant delay reduces Patent Term Adjustment. Every extension of time taken during prosecution counts against you day for day, so a patent that took four years to grant because the applicant was slow gets less term than one that took four years because the Office was.

Statutory disclaimer under 35 U.S.C. 253 lets a patentee formally give up claims or the whole patent. Rare, and usually a litigation tactic rather than a lifecycle event.

How many patents actually expire early

Computed from every maintenance fee event the USPTO has recorded — 27,273,654 rows covering 8,262,336 US utility patents granted since 1981.

The proportion expiring early is rising, from 48.9% for the 2000 cohort to 58.6% for 2014. Fee increases explain most of it — the 11.5-year large entity fee went from $3,100 in 2001 to $8,280 in 2025, a 167% rise against roughly 80% cumulative inflation.

Where the attrition happens:

Each escalation produces a larger drop-off. The third fee alone removes 23.2 percentage points of the original cohort — more than one patent in five that survived eleven years is released at that point.

But if you have already paid, you are unlikely to stop. Of owners who paid the first fee, 74.3% paid the second. Of those, 63.0% paid the third. The population that abandons early is largely people who never had a commercial use for the patent.

Full figures by grant year are on the Ipiry Patent Survival Curve.

What expiry actually means

The exclusive right ends completely. Anyone may make, use, sell, offer for sale or import the claimed invention. No permission, no royalty, no notice, no negotiation.

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, and a patent that expired last year can still support a suit over conduct from three years ago.

Post-expiry royalties are unenforceable. A licence requiring payment for use after the patent has expired is unenforceable as to that period, under Brulotte v. Thys (1964) and reaffirmed in Kimble v. Marvel (2015). This catches licensors more often than it should. A licence agreement that does not address expiry can leave one party collecting nothing and the other paying for permission they no longer need.

The specification stays public and remains prior art against later applications. Expiry removes the right to exclude; it does not remove the teaching. A published patent that expired in 1998 can still invalidate an application filed today.

The patent number stays valid for citation, for prior art searching, and for establishing what was known when. Expired patents are a substantial part of the prior art landscape and are searched routinely.

Checking whether a specific patent has expired

USPTO Patent Center is the authoritative source. Look the patent up 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. Work out the fee dates from the grant date — 3.5, 7.5 and 11.5 years — and check each one that has passed.

What indicates expiry: a window and its six-month grace period both closed with no payment recorded against them.

What to be careful about. A patent inside a grace period is still in force even though the window has closed, so a missing payment does not always mean expiry. The record can lag actual payment by a short period. 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. Relying on a database snapshot to conclude a patent is dead is how freedom-to-operate opinions go wrong.

Can an expired patent be revived?

Term expiry: no. There is no mechanism to extend a patent past its statutory term once it has run. Patent Term Adjustment and Patent Term Extension both operate before expiry, adding days or years to a term that is still running, not resurrecting one that has ended.

Lapse for non-payment: sometimes. Under 37 CFR 1.378 you may petition to accept a delayed maintenance fee if the entire delay — from the due date to the petition — was unintentional. That requires the outstanding fee, a petition fee, and a statement. It is discretionary.

Unintentional is a forgiving standard but not unlimited. Forgetting counts. A docketing failure counts. An address that went stale counts. What does not count is a deliberate decision not to pay, later regretted because circumstances changed — a patent abandoned on purpose and then revived because a competitor emerged is not an unintentional delay.

Intervening rights: why revival is worth less than it looks

Anyone who began practising the invention in good faith while the patent was lapsed may be permitted to continue. They looked at the record, saw an expired patent, and acted on it. The law does not penalise that.

The practical consequence is specific and unwelcome. The companies most likely to have started during the lapse are the ones who were watching the patent — which is to say the most likely infringers and the most likely buyers. A revived patent can be enforceable against everybody except the people who mattered.

Revival is therefore worth most when the lapse was short and least when years have passed. A patent revived three months after lapse is close to whole; one revived after two years may be a materially different asset.

Using technology from an expired patent

An expired patent is genuinely free to practise. Two checks before relying on that.

Check the family. Continuations, divisionals and continuations-in-part have their own grant dates and their own maintenance fee schedules. A parent expiring tells you nothing about whether a child covering adjacent claims is still in force. Families are commonly structured so that later members outlive earlier ones, and the one you found may be the one that ended first.

Check for other patents entirely. Freedom to operate is not established by one patent being dead. A product typically reads on claims from several patents held by several owners, and a proper freedom to operate analysis examines the whole space rather than the one patent somebody happened to mention.

Check the jurisdiction. Patents are national rights. A US patent expiring says nothing about the European, Chinese or Japanese member of the same family, each of which has its own term and its own renewal schedule. A product sold internationally needs clearance in each market.

Expiry abroad

Most countries charge annual renewal fees, usually called annuities, rather than the three-stage US structure. The amount escalates each year — small early, substantial by year fifteen — and many jurisdictions charge on pending applications as well as granted patents.

A patent lapsing in one country has no effect elsewhere. Owners routinely allow protection to lapse in markets they do not serve while maintaining it where they sell, which is ordinary portfolio management rather than neglect.

Which means "has this patent expired" is always a per-country question. The US answer and the European answer for the same invention are frequently different.

If your own patent is approaching expiry

Term expiry is not a decision. If twenty years are running out there is nothing to do but plan for the invention becoming free — which mostly means deciding whether a continuation with different claims is worth pursuing while the family is still pending.

A maintenance fee deadline is a decision, and it determines whether your patent joins the 41.4% or the 58.6%.

The question is whether four more years of exclusivity is worth the fee in front of you, and that depends on whether anyone is practising the invention, whether the technology is still current, and what the patent would fetch if sold.

A patent sold before the window closes is worth something. One that lapsed last month is worth nothing. Both outcomes end the fee obligation; only one pays you. That asymmetry is why patent valuation usually happens at a fee deadline rather than at any other point in a patent's life.

Before a fee deadline

1. Confirm the exact date from the grant date, and note the grace period end as well as the window close.
2. Check the correspondence address of record is somewhere you actually read.
3. Establish whether anyone is practising the invention — that is the difference between an asset and a cost.
4. Get a valuation while the patent is still alive.
5. If you will not pay, offer it for sale first. The buyer inherits the fee.
6. Check the rest of the family, because letting one member lapse may or may not matter depending on what the others cover.
7. Decide deliberately. Letting a patent expire is often correct. Letting it expire without knowing what it was worth is not.