How long will a patent last is a different question from how long a patent lasts in general, and the difference matters if you own one.
The general answer is twenty years from filing. That is the statutory maximum for a US utility patent.
The specific answer for your patent is almost always less, and working out by how much takes four pieces of information, three of which are printed on the document itself.
Most patents never reach the maximum. Only 41.4% of US utility patents granted in 2014 were still in force at the end of their term. The other 58.6% ended early because an owner decided the remaining life was not worth the fee.
The four inputs
| Input | Where to find it | Effect on term |
|---|---|---|
| Earliest non-provisional filing date | Front page, field (22) | The 20-year clock starts here |
| Patent Term Adjustment | Front page, near the filing data | Adds days |
| Terminal disclaimer | Front page notice, or the file wrapper | Cuts term back to an earlier patent's date |
| Maintenance fee status | USPTO Patent Center | Ends the patent early if unpaid |
The first three give you the theoretical expiry date. The fourth decides whether the patent actually gets there.
The provisional trap. If the patent claims priority to a provisional, the 20-year clock runs from the non-provisional filing date, not the provisional one. People routinely subtract a year they should not, and undervalue a patent as a result.
Working out the expiry date
Step one: find the filing date. On the front page, field (22) is the filing date of the application that issued. If there is a continuation or divisional in the chain, use the earliest non-provisional filing date in that chain, shown in "Related U.S. Application Data."
Step two: add twenty years.
Step three: add Patent Term Adjustment. PTA is printed on the front page as a number of days. Add them.
Step four: subtract for any terminal disclaimer. If one was filed, the patent expires when the earlier related patent does, regardless of the arithmetic above.
Step five: check for Patent Term Extension. Only relevant for pharmaceutical and medical device patents that lost time to FDA review. Up to five additional years, capped at fourteen years from approval.
| Adds or subtracts | Typical size | |
|---|---|---|
| Patent Term Adjustment | Adds | 0 to several hundred days |
| Patent Term Extension | Adds | Up to 5 years, pharma and devices only |
| Terminal disclaimer | Subtracts | Whatever aligns it to the earlier patent |
| Unpaid maintenance fee | Ends it | Immediately at end of grace period |
See patent term adjustment for how PTA is calculated and how to challenge a figure you think is wrong, and patent expiration date for the full calculation including the edge cases.
The maintenance fee schedule is the real constraint
Three fees, at 3.5, 7.5 and 11.5 years after grant. Not after filing — after grant, which is a date that can be years later.
| Fee | Due | Large entity | Small (40%) | Micro (20%) |
|---|---|---|---|---|
| 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 |
Each fee has a six-month grace period with a surcharge. Miss the end of that window and the patent expires permanently, without notice.
The fees escalate deliberately. The third fee is nearly four times the first, and it falls due when the patent has around eight years of enforcement window left. That structure is designed to make owners re-examine whether the patent still earns its keep, and it works.
See patent maintenance fees for the windows and what happens when one is missed.
What actually happens: the survival data
Renewal behaviour is the best available evidence on how long patents last in practice, because it records what owners decided about patents they already held.
| Ipiry Patent Survival Curve v1.0 | Rate |
|---|---|
| Survive the 3.5-year fee (2022 cohort) | 85.8% |
| Survive the 7.5-year fee (2018 cohort) | 64.6% |
| Reach full term (2014 cohort) | 41.4% |
| Abandoned before full term | 58.6% |
| Lost at the first fee | 14.2% |
| Lost at the second fee | 21.2 points |
| Lost at the third fee | 23.2 points |
| Peak full-term rate (2000 cohort) | 51.1% |
Computed from 27,273,654 USPTO maintenance fee records covering 8,262,336 US utility patents. The full dataset is at the patent survival curve.
Attrition accelerates. The first fee removes 14.2% of patents. The second removes a further 21.2 points, the third a further 23.2. Owners get more willing to let go as the fee rises and the remaining window shrinks — which is exactly the trade the fee schedule is designed to force.
Conditional survival is more useful than gross survival when you are looking at a specific patent.
| Given the owner has | They go on to pay the next fee |
|---|---|
| Paid the first fee | 74.3% of the time |
| Paid the first two | 63.0% of the time |
A patent that has already cleared two fees is a different asset from one approaching its first. Someone has now paid twice to keep it, which is a signal about the patent that no document on its face provides.
Worked example: two patents, same expiry date
Both patents expire on the same day. They are not worth the same.
Patent A — filed 2014, granted 2017, two fees paid
| Fact | Value |
|---|---|
| Non-provisional filed | March 2014 |
| Patent Term Adjustment | 210 days |
| Granted | August 2017 |
| Base expiry | March 2034 |
| Adjusted expiry | October 2034 |
| Remaining life today | ~8 years |
| First fee (Feb 2021) | Paid |
| Second fee (Feb 2025) | Paid |
| Third fee due | February 2029, $8,280 |
Patent B — filed 2014, granted 2017, first fee only
| Fact | Value |
|---|---|
| Non-provisional filed | March 2014 |
| Patent Term Adjustment | 210 days |
| Adjusted expiry | October 2034 |
| Remaining life today | ~8 years |
| First fee (Feb 2021) | Paid |
| Second fee (Feb 2025) | Missed — grace period expired |
| Actual status | Expired. Public domain since August 2025 |
Patent B's calculated term was identical. Its actual life was seven years shorter than the arithmetic said, because the arithmetic only ever gave the ceiling.
The lesson for anyone evaluating a patent: the front page tells you the maximum. Only Patent Center tells you whether the patent is alive.
The decision Patent A now faces
Eight years of life left, and $8,280 due in 2029.
| Question | Bearing on the decision |
|---|---|
| Does anyone practise the claims? | If yes, the fee is trivial against the licensing value |
| Is the technology still current? | An eight-year window on obsolete technology is worth little |
| Could it be sold instead? | A buyer inherits the fee — and pays for the remaining life |
| What does the third fee buy? | Roughly eight more years of exclusion |
The sale option is the one most owners miss. A patent sold before the fee deadline is worth something. The same patent a month after the grace period ends is worth nothing at all, and both routes end the fee obligation.
See patents for sale for who buys and what they pay for.
Remaining life and value
Buyers discount hard for a short window, because enforcement takes years. Filing suit, reaching claim construction and getting to trial can consume three to five years on its own. A patent with four years left may expire before a campaign concludes.
| Years remaining | Typical buyer | Why |
|---|---|---|
| 15+ | Any buyer | Full enforcement and licensing runway |
| 10–15 | Strategic buyers, IP funds | Enough time for a licensing programme |
| 7–10 | Operating companies, NPEs | Workable for assertion if infringement is clear |
| 5–7 | NPEs, licensing campaigns | Tight, but viable where evidence is strong |
| 3–5 | Tactical buyers | Usually defensive or portfolio-completion motives |
| Under 3 | Rarely anyone | Expires before most disputes conclude |
Remaining life is not the only value factor, but it is the one that acts as a multiplier on all the others. A strong patent with two years left and a weak patent with two years left converge toward the same number.
Which means timing the sale matters more than most owners realise. The window in which a patent is both proven and long-lived is narrower than the term suggests, and it closes quietly.
Design patents are different
Fifteen years from grant, no maintenance fees, for design patents filed on or after 13 May 2015. Earlier ones ran fourteen years.
No fees means no attrition. Design patents almost always run their full term, because nothing has to be actively done to keep them alive. The 58.6% abandonment figure applies to utility patents only.
The term also runs from grant rather than filing, so pendency does not eat into it. A design patent that took two years to issue still gets its full fifteen years.
Older patents follow a different rule
Patents filed before 8 June 1995 ran seventeen years from grant, not twenty from filing. The change came with the GATT/TRIPS implementation, and it still matters when you are looking at anything from that era.
| Filing date | Term |
|---|---|
| Before 8 June 1995 | 17 years from grant |
| 8 June 1995 or later | 20 years from earliest non-provisional filing |
| Pending on 8 June 1995 | The longer of the two |
The transitional rule is the awkward one. Applications pending on that date received whichever term was longer, which is why a handful of mid-1990s patents have expiry dates that look wrong under either rule alone.
Anything filed before June 2015 has now expired or is nearly there. If you are looking at a patent from the 1990s for freedom-to-operate purposes, it is almost certainly in the public domain — but confirm rather than assume, because Patent Term Extension can push pharmaceutical patents well past the expected date.
Plant patents and the third category
Plant patents last 20 years from filing, the same as utility patents, and like design patents they carry no maintenance fees. They cover asexually reproduced plant varieties.
| Type | Term | Maintenance fees | Runs full term? |
|---|---|---|---|
| Utility | 20 years from filing | Three | 41.4% do |
| Design | 15 years from grant | None | Almost always |
| Plant | 20 years from filing | None | Almost always |
Only utility patents have the attrition problem, because only utility patents require anyone to do anything to keep them alive.
How long will a patent last outside the US
Twenty years from filing is close to universal. What differs is how you pay to keep it.
| United States | Most other jurisdictions | |
|---|---|---|
| Term | 20 years from filing | 20 years from filing |
| Payment structure | Three fees at 3.5 / 7.5 / 11.5 years | Annual renewal fees (annuities) |
| Fees on pending applications | None | Often payable while still pending |
| Cost trajectory | Escalates in three steps | Escalates every single year |
Annuities change the arithmetic. Because foreign renewal fees rise annually and are payable in every country separately, a family kept alive across four jurisdictions can cost more each year than the US patent costs across its entire life. Owners tend to prune foreign coverage country by country, keeping the markets that matter and dropping the rest.
Which means a patent family rarely lasts the same length everywhere. When evaluating an international portfolio, the term question has to be asked per jurisdiction, not once.
Checking how long someone else's patent will last
The most common reason to ask this question is not about your own patent. It is about a patent that blocks you.
| What you need | Where | Why |
|---|---|---|
| Expiry date | Front page arithmetic plus PTA | The ceiling |
| Maintenance fee status | USPTO Patent Center | Whether it is still alive |
| Terminal disclaimer | Front page, file wrapper | May expire earlier than calculated |
| PTE | Front page notice | Pharma patents may last far longer |
| Assignment history | USPTO Assignment Search | Who to approach |
A blocking patent with two years left is a waiting problem, not a legal one. Designing around costs money; waiting costs time. Which is cheaper depends entirely on the remaining term, and that calculation is worth doing before paying for a design-around.
Watch the next fee date. A blocking patent approaching an $8,280 third fee has a meaningful chance of simply being abandoned — 23.2 points of the cohort drops out at that stage. See freedom to operate for how in-force status drives clearance analysis.
How long will a patent last: the checklist
- Find the earliest non-provisional filing date. Field (22), or the earliest date in Related U.S. Application Data if there is a continuation chain.
- Do not subtract for a provisional. The term runs from the non-provisional filing. Counting the provisional year is the most common mistake in this calculation.
- Add twenty years.
- Add the Patent Term Adjustment printed on the front page.
- Check for a terminal disclaimer. If one exists, the patent expires with the earlier related patent regardless of your arithmetic.
- Check for Patent Term Extension if it is a pharmaceutical or medical device patent. Up to five years, capped at fourteen from approval.
- Look up maintenance fee status in USPTO Patent Center. This is the step that distinguishes a live patent from an expired one, and the front page will not tell you.
- Identify the next fee date and amount, and diarise it at least three months before the window closes.
- Decide before the window, not during it. Keep, sell or let lapse — all three are legitimate, but only two of them are available if you wait.
- Re-run the calculation at every fee deadline. Remaining life falls, the fee rises, and the answer that was right at 3.5 years is frequently wrong at 11.5.