A 37 CFR 1.136(a) extension of time lets a patent applicant buy up to five additional months to respond to a USPTO Office action in one-month increments, simply by paying a tiered fee and filing a petition. No explanation is required, and the extension is granted effectively automatically. The cost comes in two forms: the fees rise steeply with each added month, and any response filed more than three months after the Office action mailing date reduces your patent term adjustment day for day.
The Six-Month Ceiling Sets Your Maximum Extension
Federal law gives every applicant a hard six-month window to respond to an Office action. Miss it, and the USPTO treats the application as abandoned under 35 U.S.C. 133.1Office of the Law Revision Counsel. 35 USC 133 – Time for Prosecuting Application
You almost never see the full six months printed on the action itself. The Director sets a “shortened statutory period” on virtually every Office action, typically two or three months, and that shorter deadline is what governs how many months of extension you can request. The shortened period can never be less than 30 days.
The arithmetic is simple. Add the shortened period to any extension, and the total cannot exceed six months. A three-month shortened period leaves room for a three-month extension. A two-month shortened period leaves room for four.
How the Automatic Mechanism Works
Unlike most USPTO petitions, a 1.136(a) petition does not require you to explain why you need more time. File the petition, pay the fee, submit your response.
You do not need to file the petition before the original deadline passes. The regulation looks at the date you actually pay the fee and file the petition to decide which month of extension applies and what the fee will be. If your Office action set a three-month period and you file your response along with the petition and fee during the fourth month, the USPTO treats that as a one-month extension.
Experienced practitioners often skip the separate petition entirely by placing a blanket authorization in the file. An authorization to charge all required fees, or all extension-of-time fees under 37 CFR 1.17, to a deposit account operates as a “constructive petition” for whatever length of extension the late reply requires.2eCFR. 37 CFR 1.136 – Extensions of Time Miscount the deadline by a few days and the extension applies without a separate filing.
Current Extension Fees
Fees increase steeply with each additional month and vary by entity size. Small entities pay 40% of the large-entity rate; micro entities pay 20%. The 2026 schedule:
- First month: $235 (large), $94 (small), $47 (micro)
- Second month: $690 (large), $276 (small), $138 (micro)
- Third month: $1,590 (large), $636 (small), $318 (micro)
- Fourth month: $2,495 (large), $998 (small), $499 (micro)
- Fifth month: $3,395 (large), $1,358 (small), $679 (micro)
Each line is a standalone fee for that specific month. If you need a two-month extension from a three-month shortened period, you pay the second-month fee ($690 for a large entity), not the sum of the first and second months.3United States Patent and Trademark Office. USPTO Fee Schedule The jump from first month to fifth month is more than fourteenfold for large entities, which is by design: the pricing discourages routine use of the full six-month window.
When 1.136(a) Is Not Available
The automatic mechanism does not apply everywhere. The regulation lists five situations where you cannot simply pay a fee and get more time:2eCFR. 37 CFR 1.136 – Extensions of Time
- The Office action itself states that 1.136(a) extensions are not available.
- A reply brief filed after an examiner’s answer before the Patent Trial and Appeal Board.
- A request for oral hearing before the Board.
- A response to a decision by the Board, including a decision on appeal.
- An application involved in a contested case or a derivation proceeding.
Automatic extensions are also unavailable in ex parte reexamination proceedings. There, extensions require a showing of sufficient cause and the request must be filed before the due date passes.4United States Patent and Trademark Office. Manual of Patent Examining Procedure – Extension of Time
When 1.136(a) is off the table, the fallback is 37 CFR 1.136(b). That provision requires a demonstration of “sufficient cause” and the Office grants a “reasonable time,” exercising real discretion over whether to approve the request.2eCFR. 37 CFR 1.136 – Extensions of Time
How to File the Petition
The USPTO offers two filing paths.
ePetition
For most applicants this is the faster option. You enter the required information into a secure web interface, pay the fee, and receive a decision immediately. There is no form to upload and no waiting period; the extension is granted on the spot.5United States Patent and Trademark Office. ePetition Resource Page
Form PTO/AIA/22
The form-based route uses PTO/AIA/22, which asks for the application number, filing date, art unit, the assigned examiner’s name, and the number of months requested.6United States Patent and Trademark Office. Petition for Extension of Time Under 37 CFR 1.136(a) You submit through Patent Center, the USPTO’s sole electronic filing platform since the retirement of EFS-Web.7United States Patent and Trademark Office. Patent Center Fully Replaces USPTO Legacy Systems for Filing and Managing Patent Applications Payment goes on a credit card or a USPTO deposit account, and the system returns an Electronic Acknowledgement Receipt confirming filing date and documents received.
The Patent Term Adjustment Cost
Every day you take beyond three months to respond to an Office action reduces your patent term adjustment day for day. This is true regardless of what the shortened statutory period on the action says. Even if the examiner set a three-month deadline and you filed during month four with a proper extension, you still lose PTA for every day past the three-month mark.8eCFR. 37 CFR 1.704 – Reduction of Period of Adjustment of Patent Term
The clock starts the day after the three-month mark from the mailing date of the Office action and runs until the day you file your reply. Respond on day 100, roughly three months and ten days, and you lose ten days of patent term adjustment. File at the five-month mark and you lose about 60 days. For patents where each day of enforceable life carries meaningful value, that trade-off deserves a real look before paying for extension months you may not need.
What Happens If You Miss the Six-Month Deadline
Fail to respond within the six-month statutory maximum and the application is deemed abandoned. Abandonment is not necessarily permanent, but revival is more expensive and more involved than any extension would have been.
To revive, you file a petition under 37 CFR 1.137 that includes a statement that the entire delay was unintentional, the response that should have been filed originally, and the petition fee.9eCFR. 37 CFR 1.137 – Revival of Abandoned Application The fee depends on how long the application stayed abandoned:
- Delay of two years or less: $2,260 (large), $904 (small), $452 (micro)
- Delay of more than two years: $3,000 (large), $1,200 (small), $600 (micro)
These figures exceed even the fifth-month extension fee.10United States Patent and Trademark Office. USPTO Fee Schedule The Director can also require additional evidence that the delay was truly unintentional, and some application types require a terminal disclaimer that shortens the patent term by the length of the abandonment period.