How Long Does a Patent Last? (And What Happens When It Expires)

Most people know patents don't last forever. Few know exactly how long they last, what shortcuts the term, what extends it, and what happens to an invention the day after protection expires.

The answer depends on what type of patent you're talking about.

Utility patents: 20 years from filing

The standard US utility patent lasts 20 years from the application's filing date — not from the date it's granted. This distinction matters. An application filed in 2005 that takes five years to work through the patent office and is granted in 2010 expires in 2025 (20 years from 2005), not 2030.

The effective term of market exclusivity is therefore shorter than 20 years for patents that face long examination periods. This is particularly significant in pharmaceuticals, where drug development timelines mean a drug might reach market with only 8–12 years of patent protection remaining.

Congress addressed this with Patent Term Adjustment (PTA), which adds days back to a patent's term to compensate for USPTO delays. A patent that spent 3 years in prosecution might receive hundreds of days of PTA, effectively extending its expiration.

In pharmaceuticals, an additional tool — the Patent Term Extension (PTE) — can add up to 5 years to compensate for regulatory review time at the FDA. This is why some drug patents effectively last longer than 20 years.

Design patents: 15 years from grant

Design patents — which protect the ornamental appearance of an object rather than its function — last 15 years from the date of grant. (This was changed from 14 years by the Patent Law Treaties Implementation Act of 2012 for patents issued on or after May 13, 2015.)

Unlike utility patents, design patents:

• Are measured from grant date, not filing date
• Require no maintenance fees
• Cannot receive term extensions

Plant patents: 20 years from filing

Plant patents, which protect asexually reproduced distinct and new varieties of plants, follow the same 20-year-from-filing rule as utility patents. They also do not require maintenance fees.

Maintenance fees: the hidden expiration trigger

A utility patent doesn't automatically stay in force until its 20-year expiration. The patent holder must pay maintenance fees at specific intervals:

• 3.5 years after grant: $950 (large entity) / $475 (small entity) / $237.50 (micro entity)
• 7.5 years after grant: $1,950 / $975 / $487.50
• 11.5 years after grant: $3,150 / $1,575 / $787.50

Miss a payment, and the patent lapses. It can sometimes be revived with a petition and surcharge, but there are time limits. Many patents expire early because holders decide the maintenance cost exceeds the value of continued protection.

This is commercially significant. A portfolio of 500 patents might have 50 patents that lapse at the 7.5-year mark because the relevant products have been discontinued. The remaining claims still in force are the ones worth monitoring.

What "expired" means in practice

When Alexander Graham Bell's telephone patent (US174465) expired in 1893, the result was immediate and dramatic. Within a few years, hundreds of telephone companies formed across the United States. Rates dropped. Rural access expanded. Bell's company — which would become AT&T — maintained dominance through network effects and infrastructure, not patents.

When a patent expires:

• Anyone can make, use, sell, and import the invention without a license
• No royalties are owed to the former patent holder
• The invention is in the public domain — permanently, and irrevocably
• Competitors can describe the technology accurately in their marketing
• New patents can be filed on improvements — but not on the original expired invention

The patent cliff in pharmaceuticals

The pharmaceutical industry tracks patent expirations with surgical precision. When a blockbuster drug's last relevant patent expires, generic manufacturers can immediately file for FDA approval of equivalent drugs. Generic entry typically drops drug prices by 80–90% within 12–18 months.

Companies respond by building "patent thickets" — multiple overlapping patents on different aspects of a drug (formulation, dosage form, method of treatment, delivery mechanism) that expire at different times, extending effective protection. This practice is controversial and subject to antitrust scrutiny in some contexts.

Expired patents as opportunity

For technologists and product companies, expired patents are an underappreciated resource. Many fundamental technologies — core smartphone components, essential internet protocols, foundational machine learning algorithms — have expired or will expire in the next decade.

Browsing PatentBrief's expired patents collection lets you see what's recently entered the public domain. When a patent expires on a manufacturing process or technical approach, that expiration can represent a genuine competitive opportunity for companies that have been waiting.

The iPhone's original design patents are expiring in the mid-2020s. What happens to "the smartphone aesthetic" when anyone can legally replicate it? That's not a hypothetical — it's an ongoing market dynamic.

PatentBrief is not a law firm. Nothing here is legal advice.