How to Check if a Patent Is Still in Force

Before licensing a patent, designing around one, or assuming a competitor's patent has expired, you need to verify its legal status. A granted patent can be inactive for several reasons — expired term, unpaid maintenance fees, successful invalidity challenge, or voluntary abandonment. This tutorial shows you how to check, office by office.

Why Legal Status Matters

A patent that is not in force cannot be enforced. If a competitor's patent has lapsed because they missed a maintenance fee payment, you are free to practise the invention in that jurisdiction. Conversely, if you are buying or licensing a patent, you must verify it is actually alive — a patent described as "granted" may have quietly lapsed years ago.

Checking US Patents (USPTO)

Patent Center: Go to patentcenter.uspto.gov and search by patent number. The status page shows whether the patent is "Active" or "Expired," the maintenance fee payment history, and the calculated expiration date.

USPTO Patent Term Calculator: For patents subject to patent term adjustment (PTA) or patent term extension (PTE), the actual expiration date may differ from the simple "filing date + 20 years" calculation. Patent Center displays adjusted expiration dates.

Key maintenance fee dates (US):

• 3.5 years after grant
• 7.5 years after grant
• 11.5 years after grant

If any maintenance fee is missed, the patent lapses. There is a 6-month grace period (with a surcharge) after each deadline. After the grace period, the patent expires — though petition-based revival is possible in limited circumstances.

Checking European Patents (EPO)

European Patent Register: Go to register.epo.org and search by publication number. The register shows the procedural status, opposition status, and renewal fee payment history.

Critical distinction: A granted European patent is maintained through annual renewal fees paid to each national office where the patent has been validated — not to the EPO centrally. A European patent may be in force in Germany but lapsed in France because the French renewal fee was not paid. You must check each validated country separately.

National registers for validated EP patents: DPMA (Germany), INPI (France), UKIPO (UK), OEPM (Spain), and each national office where the patent was validated. Espacenet's INPADOC legal status tab provides a consolidated view.

Checking Chinese Patents (CNIPA)

CNIPA Patent Search: Go to english.cnipa.gov.cn or use the CEPIS database. Search by patent number. The legal status shows whether annual fees have been paid and whether the patent is active, terminated, or under reexamination.

Chinese patents require annual maintenance fees starting from the year of grant. If an annual fee is missed, there is a 6-month grace period with a surcharge. After the grace period, the patent terminates.

Checking Japanese Patents (JPO)

J-PlatPat: Go to j-platpat.inpit.go.jp and search by patent number. The "Legal Status" tab shows the current status, annual fee payment history, and any trials for invalidation.

Japanese patents require annual fees from the year of registration. The JPO provides detailed payment records through J-PlatPat.

Checking Multiple Jurisdictions at Once

Espacenet INPADOC: The fastest way to check a patent family's status across multiple countries. From any patent on Espacenet, click the "INPADOC legal status" tab to see events across all family members — grants, lapses, oppositions, and fee payments in every jurisdiction.

The Lens (lens.org): A free patent database that aggregates legal status information from multiple offices and presents it in a clean, searchable interface.

What Each Status Means

Sources

1. USPTO — Patent Public Search — US patent status lookup and maintenance fee records
2. EPO — European Patent Register — Legal status information for European patents
3. Espacenet — Patent family and legal status data from offices worldwide
4. Google Patents — Free patent search with status information
5. WIPO PATENTSCOPE — PCT application status and national phase entry information