A petty patent is protected for an initial 6 years from the filing date, and can be renewed twice for up to 2 years each time, for a maximum total protection period of 10 years. The owner must file each renewal application with the Department of Intellectual Property within the legally required window, or protection ends at the original expiration date with no way to restore it.
How Many Times Can You Renew, and For How Long
Under the petty patent provisions of Thailand's Patent Act B.E. 2522 (Chapter 3 bis), a petty patent is protected for an initial 6 years from the filing date, and the owner may file for renewal twice, for up to 2 years each time, for a maximum total protection period of 10 years from the original filing date - shorter than an invention patent, which is protected for a fixed 20 years with no renewal mechanism at all.
When You Must File a Renewal
The owner must file the renewal application with the Department of Intellectual Property within 90 days before each expiration date - both for the first renewal (from year 6 to year 8) and the second (from year 8 to year 10). Tracking that expiration date is the owner's responsibility, just as with a trademark: the Department of Intellectual Property has no mandatory automatic reminder system.
The Renewal Filing Process
In general, the petty patent owner (or an authorized patent agent) files the renewal request and pays the applicable fee with the Department of Intellectual Property on the prescribed form, citing the original petty patent number and the renewal period being requested. If an agent files on the owner's behalf, a power of attorney in the department's required form must be attached.
Fees Involved in Renewal
Renewing a petty patent involves a government fee charged by the Department of Intellectual Property under its current fee schedule, always kept clearly separate from Patent To You's own professional service fee whenever you use our services. Because government fee schedules are updated periodically, we recommend confirming the current rate directly with the Department of Intellectual Property, or asking our team to calculate the exact cost as of your actual filing date.
What Happens If You Miss the Deadline
If the legally required filing window passes without a renewal application, the petty patent's protection ends at the original expiration date (year 6 or year 8, as applicable). The invention then falls into the public domain - others may use it without infringing - and the original owner has no way to reclaim the lapsed protection. The only remaining option is to file an entirely new application, which takes effect only from its own new filing date, and carries a real risk that the invention no longer meets the novelty requirement, since it was already disclosed publicly during the period it was previously protected.
How to Avoid Missing a Renewal Deadline
Since the Department of Intellectual Property has no obligation to send advance reminders, a business holding a petty patent should set its own advance-warning system - for example, a calendar reminder several months ahead of the 90-day filing window - or have a registered patent agent track the expiration date and file the renewal on its behalf. This matters even more for businesses holding several petty patents with different expiration dates, where tracking everything from one central point reduces the risk of missing any single deadline.
FAQ
How many times can a petty patent be renewed, and for how long each time?
It can be renewed twice, for up to 2 years each time, for a maximum total protection period of 10 years from the filing date. Each renewal application must be filed within 90 days before the expiration date.
If I forget to renew a petty patent and it expires, can I file a new one?
You can file a brand-new application if the invention has not been publicly disclosed in a way that destroys its novelty, but it gets a new filing date - not the original one - as its priority date, and there is no mechanism to restore the original, lapsed petty patent. Track your renewal deadlines closely to keep your rights continuous.
