It is a common moment in many industries. A drug goes off patent, a technology standard names an expired filing, or a startup finds a 2008 patent that looks perfect for its new product. The next question is immediate, and practical. If the term of patent protection is over, can the invention be used by anyone without asking or paying? Indian law gives a clear starting point, but there are important caveats that smart teams consider before scaling production.
The 20-year rule, and what exactly “expiry” means
Under Section 53 of the Patents Act, 1970, the term of a patent in India is 20 years. For a regular application, the 20 years are counted from the filing date in India. For a PCT national phase, the 20 years are counted from the international filing date. Once that term ends, the exclusive rights conferred by Section 48 cease. In practical terms, the claims can no longer be enforced against use, making, selling, importing or offering for sale in India.
Two quick clarifications that often save time:
The 20 years run from filing, not from grant. A patent granted after a long examination still ends 20 years from the original filing or international filing date.
There is no patent term extension or supplementary protection certificate in India for regulatory delay. When the clock runs out, it runs out.
Does everything become free? Mostly yes, but check these roadblocks
When a patent expires, the claimed invention enters the public domain. Anyone may use the disclosed and claimed subject matter in India without licence. However, “free to operate” is not always the same as “risk free”. Before committing tooling and marketing budgets, teams should run through these checkpoints.
1) Are there other live patents that still bite?
It is common to find families and layers of protection. A core patent may have expired, but:
Divisional applications under Section 16 can sit alongside the parent. They generally share the parent’s filing date, so their terms usually end with the parent. Still, confirm the actual status because different claim sets may have been granted at different times.
Patents of addition normally expire with the main patent under the Act, but it is worth checking whether any addition matured into an independent patent for a residual term.
Improvement or follow-on patents owned by the same or different parties may still be in force. Your product could practice the expired claims and still infringe a later improvement claim. A quick freedom-to-operate scan of adjacent IPC classes and cited references is good practice.
2) Was the patent truly “in force” until the end?
Patents can lapse early for non-payment of renewal fees and may be restored. If a patent lapses and is later restored, Section 62 places limits on suing for acts during the lapse and allows conditions to protect those who began use in good faith. For a product roadmap, this means: do not assume a lapsed status is permanent until you check whether a restoration application is pending or allowed.
3) Regulatory and sectoral gates still apply
Even when the invention is free from patent control, regulatory approvals can be mandatory. For medicines, devices, agro-chemicals or food tech, the freedom from patent does not replace approvals under sector laws. Indian law also has a Bolar-style exemption in Section 107A, which lets competitors do regulatory work before expiry so they can launch immediately after. If you are planning a first-day launch, ensure your own regulatory steps are aligned.
4) Other IP may survive the patent
Brand names remain protected by trade mark law. Manuals, GUIs and marketing creatives are covered by copyright. Product shapes might be covered by design registrations. If you refer to the original patentee’s brand or copy their content, different IP risks arise even though the technical invention is now public.
5) Contractual and standards issues
If the technology is part of a standard, implementers may need to follow the standard’s licensing framework, even when a particular essential patent in that stack has expired. Also check any NDAs or licenses you previously signed. Contract terms can outlive the patent term.
Counting to 20 the right way, with common edge cases
Founders and engineers often ask variations of the same three questions:
Is the 20-year patent term ever different for Indian filings?
For ordinary and convention filings, it is 20 years from the Indian filing date. For PCT national phase entries, it is from the international filing date, not the Indian national phase date. Section 53 makes this explicit.
What if examination delays were very long, can time be added back?
Indian law does not provide patent term adjustment or extension. Courts have consistently applied the statute as written. Once the Section 53 term ends, exclusivity ends.
Do divisionals or continuations keep the invention locked up longer?
A divisional gets the parent’s filing date under Section 16, so its term usually ends the same day as the parent. The practical risk is not a longer term, but different claim language that might still capture your product while the parent is close to expiry. Map your features against every live claim set in the family, not just the earliest patent.
How to use an expired patent safely, step by step
A short, repeatable checklist helps teams move from legal comfort to operational readiness.
Confirm legal status: Pull the latest status of each patent number in the family, including divisionals, additions and Indian counterparts of foreign filings. Check expiry dates, renewal history and any restoration proceedings on record.
Read the claims first, then the drawings: Post-expiry, the claims define what is now open to use. If your planned product omits a claim element, you may be using only part of the disclosure. That is fine, but competitors can also use the full claim. If your planned product adds features that are covered by a later, live patent, adjust early.
Cross-check adjacent patents: Search for later patents citing the expired one, or patents by the same assignee in the same IPC subclass. These are the usual places where improvement claims sit.
Plan branding and presentation: Use your own marks and original content. Avoid implying an association with the former patentee. If you must reference the expired patent in technical literature, cite it factually, for example “Based on the invention disclosed in INXXXXXX, now expired”.
Align regulatory and quality milestones: For regulated products, file and complete approvals in time to launch after the patent term ends. Section 107A supports pre-expiry testing and submissions, but manufacturing for sale must wait until expiry.
Document your freedom-to-operate analysis: Keep a dated memo of the search, claim charting and status checks. If questions arise later, this record shows diligence and can help de-risk investment decisions.
Pricing, supply and competition after expiry
The business landscape typically shifts quickly once a high-value patent expires. Expect new entrants, price competition and faster iteration. Early movers who prepared during the tail end of the patent term often secure relationships with distributors and OEMs immediately after day zero. Conversely, if you are the outgoing patentee, consider defensible positions that survive expiry, such as branding, service quality, supply chain scale, and proprietary know-how that was never disclosed.
Using the disclosure as a technical springboard
Expired patents are excellent technical resources. The specification and drawings remain public and can be used to teach teams or benchmark designs. The best approach is to treat the disclosure as open literature while recognising that some manufacturing know-how may not be fully described. A pilot build or reverse-engineering sprint can bridge any gaps before you commit to tooling.
Litigation status and remedies near the end of term
If you are defending an infringement suit and the patent expires during litigation, the injunction question becomes moot for future acts because exclusivity ends with the term. However, past damages or accounts of profits may still be pursued for the period when the patent was in force. Settlement decisions should reflect this split between past liability and future freedom. If you are asserting a patent approaching its end, prompt action is critical because interim injunctions are discretionary and the window for meaningful relief narrows as expiry nears.
A compact table for quick reference
Topic | Indian position |
Statutory term | 20 years from filing date, or from international filing date for PCT national phase, per Section 53 |
Rights after expiry | Section 48 rights cease, invention enters public domain, free to use in India |
Term extension | Not available in India |
Lapse and restoration | Lapse on non-payment of renewal. Restoration possible. Acts during lapse face protections and conditions under Section 62 |
Divisionals | Same filing date as parent under Section 16, term typically ends with parent |
Patent of addition | Generally expires with main patent |
Pre-expiry regulatory work | Permitted under Section 107A, but commercial sales must await expiry |
Bringing it together
The rule is simple, the practice is not. When a patent’s 20-year term ends, exclusivity ends with it, and the invention can be used by anyone in India. Teams that pair this clarity with a careful sweep for live improvement patents, a plan for regulatory steps, and clean branding usually capture the post-expiry opportunity without surprises. Whether you are entering a market newly opened by expiry or planning around your own portfolio’s sunsets, a short, disciplined freedom-to-operate exercise is the difference between a smooth launch and an avoidable detour.
