Kafantaris Law Group | Theo Kafantaris
Maintenance fees are due at 3.5 years, 7.5 years, and 11.5 years after issuance without a surcharge. A maintenance fee can be paid up to 6 months after these dates (4 years, 8 years, 12 years), but they will then include a surcharge. If you have past your 6 month late payment window, a petition can be filed in certain circumstances to reinstate an expired patent, but the chances of success are fairly low. Feel free to contact me for an explanation of your options if you fall in any of these categories.
Answer Applies to: California