US Patent Expiration Calculator

Calculator Inputs

Patent Number

Patent Title

Patent Type

US Filing Date

Used for design cutoff and default base term.

Earliest Benefit Date

Use for continuations, divisions, or relevant PCT benefit.

Grant Date

Required for design terms and maintenance dates.

Provisional Filing Date

Stored as a note. Not used as base term date.

PTA Days

Patent term adjustment days.

PTE Days

Patent term extension days.

Terminal Disclaimer Date

Maintenance Status

As Of Date

Apply terminal disclaimer as a hard cap

Notes

Example Data Table

Scenario	Type	Filing Date	Grant Date	PTA	Expected Use
Standard utility patent	Utility	2018-04-10	2021-08-17	120	Normal portfolio review
Design filed after cutoff	Design	2017-06-01	2019-01-15	0	Design term estimate
Terminal disclaimer case	Utility	2015-02-20	2019-05-07	450	Family term comparison

Formula Used

Utility or plant base term: earliest selected filing or benefit date + 20 years.

Adjusted term: base expiration + PTA days + PTE days.

Terminal disclaimer estimate: adjusted term is capped at the disclaimer date when the hard cap box is selected.

Design term: grant date + 15 years when filed on or after May 13, 2015. Older design filings use 14 years from grant.

Maintenance review: utility fee checkpoints are estimated at 3.5, 7.5, and 11.5 years from grant, with a six month grace endpoint shown for each checkpoint.

How to Use This Calculator

Select the patent type first. This controls the main term rule.
Enter the US filing date. Add an earliest benefit date when the patent claims an earlier qualifying application.
Enter the grant date for design patents or utility maintenance checks.
Add PTA, PTE, and terminal disclaimer dates from trusted records.
Choose maintenance status to test possible early lapse scenarios.
Press calculate. Review the result, warnings, and maintenance table.
Download the CSV or PDF for docket review.

US Patent Term Planning Guide

A patent term review should start with the right patent type. Utility and plant patents usually use a twenty year clock. That clock normally begins with the earliest relevant United States filing date. Design patents use a different clock. Their term is measured from the grant date.

Why Dates Matter

Small date changes can change a result. A continuation may pull the calculation back to an earlier application. A provisional filing can help priority, yet it is not always the base term date. A PCT national stage case may need its earliest United States recognized benefit date. Because of this, the calculator separates filing, earliest benefit, and grant dates.

Adjustments and Extensions

Patent term adjustment adds days for certain examination delays. Patent term extension can add time for eligible regulatory review. These values are usually found in official records or legal review notes. Enter them as days. The tool adds them after the base term. A terminal disclaimer can shorten the term. Use the disclaimer field when a patent is tied to an earlier expiring patent.

Maintenance Review

Maintenance fees can end a utility patent before the natural term. The calculator lists the three main fee checkpoints. It also shows window opening, due, and grace close dates. If a fee is marked unpaid, the report warns that the patent may lapse earlier than the final term date. Plant and design patents do not use those fee checkpoints.

Practical Use

This calculator is best for screening, docket checks, and portfolio summaries. It helps teams compare scenarios before a formal legal review. Use it when checking freedom to operate notes, acquisition files, licensing schedules, or product launch plans. Always confirm the final answer with USPTO records, assignment history, priority claims, disclaimers, and maintenance payment status. Patent term rules can include exceptions. A careful review protects budgets, deadlines, and risk decisions.

Good records also improve communication. Save the result with the patent number, title, and notes. Share the CSV with docket staff. Send the PDF to managers. Keep assumptions visible. When dates are uncertain, run several scenarios. The difference can show whether deeper counsel review is urgent today.

FAQs

1. Is this calculator legal advice?

No. It is a planning tool. Patent terms can involve priority claims, disclaimers, extensions, corrections, and payment records. Always confirm important results with official records and qualified counsel.

2. Which date should I use for a utility patent?

Use the earliest relevant United States filing or benefit date for the main term estimate. If the patent claims continuation, divisional, or PCT benefit, review the front page and file history carefully.

3. Does a provisional date control expiration?

Usually no. A provisional date can support priority, but it normally does not start the twenty year patent term. This calculator records it as a note only.

4. How are design patents handled?

The tool uses the filing date to choose the design rule. Design patents filed on or after May 13, 2015 use fifteen years from grant. Older design filings use fourteen years from grant.

5. What is PTA?

PTA means patent term adjustment. It can add days for qualifying examination delays. Enter the official number of days if it appears in patent records or docket data.

6. What is PTE?

PTE means patent term extension. It may apply in limited regulatory review situations. Enter the approved days only after checking the official extension record.

7. Why include maintenance fees?

A utility patent may lapse before its natural term if required fees are not paid. The calculator shows the main payment checkpoints and grace close dates for review.

8. Can a terminal disclaimer shorten the term?

Yes. A terminal disclaimer may limit the patent term to an earlier date. Use the disclaimer field when your records show a limiting date or linked patent expiration.