Patent Law · 35 U.S.C. § 41
Patent Maintenance Fees
A US utility patent requires three maintenance fee payments to stay in force past 4, 8, and 12 years from grant. Missing a payment — without revival — causes the patent to expire early, opening the invention to public use before the 20-year term ends. Small and micro entities pay 50% and 80% discounts.
Key maintenance rule
Only US utility patents need maintenance fees — design and plant patents do not. The three fees are due at 3.5, 7.5, and 11.5 years from the grant date, each with a 6-month grace period. Missing all three windows lets the patent expire. Revival is available within 2 years if the delay was unintentional.
Fee schedule
Three maintenance fees — due dates and amounts
Fee amounts are subject to change. Verify current amounts on the USPTO fee schedule (37 C.F.R. § 1.20). Note: the surcharge fee (for paying during the grace period) is separate from the maintenance fee itself.
Entity size discounts
Large, small, and micro entity — who qualifies
Large entity
Full fee (100%)All entities not qualifying as small or micro — corporations, universities over threshold
Default — no qualification required
Small entity
50% discount on USPTO feesIndividual inventors, small businesses with fewer than 500 employees, non-profit organizations
Must qualify at time of payment; must update status if entity size changes (e.g., company acquired by large entity)
Micro entity
80% discount on USPTO fees (pay 20%)Must qualify as small entity AND: (1) applicant has not been named as inventor on more than 4 previously filed applications; AND (2) applicant's gross income in prior year did not exceed 3× the median household income (currently ~$239K); AND (3) applicant has not assigned rights to an entity exceeding the income limit
Strictest requirements — must certify compliance at time of payment; filing false micro entity certification is inequitable conduct
FAQ
Maintenance fee questions
When are patent maintenance fees due?
US utility patent maintenance fees are due at three points measured from the patent's grant date (not filing date): (1) 3.5-year fee: due 3 years and 6 months (42 months) after the grant date. Has a 6-month grace period with surcharge — effectively payable through 4 years after grant. (2) 7.5-year fee: due 7 years and 6 months (90 months) after the grant date. Grace period through 8 years after grant with surcharge. (3) 11.5-year fee: due 11 years and 6 months (138 months) after the grant date. Grace period through 12 years after grant with surcharge. The USPTO will send reminder notices, but the patent owner is ultimately responsible for tracking due dates. The USPTO's patent maintenance fee reminder notices go to the fee address of record — making sure the USPTO has a current fee address is critical. Missing all grace periods causes the patent to lapse. Design patents and plant patents do not require maintenance fees. Note: these are measured from the date of grant, not the filing date or priority date.
What happens if a patent maintenance fee is not paid on time?
Missing a maintenance fee by the due date does not immediately expire the patent — there is a 6-month grace period. During the grace period, the fee can be paid with an additional surcharge (currently $160 for small entities, $80 for micro entities). If the fee is paid within the grace period (with surcharge), the patent continues as if paid on time — no lapse. If the fee is still not paid by the end of the 6-month grace period, the patent lapses (expires early, before its 20-year term). A lapsed patent means: the patent is no longer in force; infringement during the lapse period cannot be recovered once the patent lapses (no retroactive damages for lapse period); third parties may begin making, using, selling, or importing the formerly-patented invention without infringement liability during the lapse period. However, a lapsed patent may be revived — see the revival question below.
Can a lapsed patent be revived, and what are the limits on revival?
Yes — a lapsed patent can be revived by petition to the USPTO, but only if the delay was unintentional and the petition is filed within 2 years of the lapse date. Under 35 U.S.C. § 41(c)(1), the USPTO may accept a petition for revival of a lapsed patent if: (1) the petition is filed within 2 years of the date the maintenance fee was due (not the end of the grace period); (2) the petition states that the delay in payment was unintentional; (3) the missed maintenance fee is paid in full with the applicable surcharge; (4) the revival petition fee is paid. The USPTO generally accepts a statement that the delay was unintentional without requiring detailed explanation — the petitioner signs the statement under oath. After 2 years from the lapse date, revival is no longer available and the patent is permanently expired. Critical exception — intervening rights (35 U.S.C. § 41(c)(2)): even after successful revival, a party who began manufacturing, using, or selling the formerly-patented invention in good faith during the lapse period has 'intervening rights' — they may continue those specific activities without infringement liability, even after the patent is revived. Intervening rights protect parties who relied on the public domain status of the lapsed patent.
How does entity size affect maintenance fees, and what is a micro entity?
USPTO patent fees (including maintenance fees) are discounted based on entity size: Large entity: pays 100% of the published fee — default for all entities not qualifying as small or micro. Small entity: pays 50% of the fee — qualifies as: individual inventors who have not assigned rights to a large entity; small businesses with fewer than 500 employees (including affiliates); qualifying nonprofit organizations. Micro entity: pays 20% of the fee (80% discount) — qualifies as: must qualify as small entity AND (1) has not been named as inventor on more than 4 previously filed patent applications (not counting provisional applications or foreign applications); AND (2) applicant's gross income in the prior year did not exceed 3× the median household income (currently approximately $239,000); AND (3) applicant has not assigned rights, and is not obligated to assign rights, to an entity with gross income over the limit. Entity status must be accurate at the time of payment. If entity status changes (e.g., individual inventor is hired by a large corporation), fees must be paid at the new entity's rate. Paying at the wrong entity size: over-paying (claiming large entity when small entity qualifies) is not a problem but wastes money. Under-paying (claiming micro or small entity when not qualified) is fraud on the USPTO and may constitute inequitable conduct, potentially rendering the patent unenforceable.
Do design patents require maintenance fees?
No — design patents do not require any maintenance fees and do not lapse due to non-payment. A design patent remains in force for its full 15-year term (for design patents granted from applications filed on or after May 13, 2015) or 14-year term (older design patents) from the grant date, with no additional payments required. Similarly, plant patents do not require maintenance fees. Only utility patents (including reissue patents of utility patents) require the three maintenance fee payments at 3.5, 7.5, and 11.5 years from grant. Design patents expire only by: (1) reaching the end of their 14- or 15-year term; (2) being declared invalid by a court or the PTAB; or (3) dedication to the public (voluntary abandonment). One practical note: if a company has a mix of design and utility patents in a portfolio, maintenance fee calendaring needs to distinguish between them to avoid inadvertently missing utility patent maintenance fees while incorrectly tracking design patents.