Term of a patent

Twenty years sounds long until you notice when the clock starts.

In simple words

Twenty years from the date of filing the application - or, for a PCT application designating India, twenty years from the international filing date - subject to renewal fees being paid.

Think of it as

The clock starts on filing day, not on grant day.

Why it matters

Grant in India commonly comes four to six years after filing. That time comes out of the twenty years, not on top of it. India has no patent term extension or adjustment mechanism, so prosecution delay is simply lost commercial life.

A simple example

File in 2026, grant in 2031, expiry in 2046. You have roughly fifteen enforceable years, not twenty.

Common mistake

Budgeting a product's commercial life from the grant date.

Where it comes from

Patents Act 1970, section 53