PCT Deadline Calculator
Use your priority date to estimate key Patent Cooperation Treaty (PCT) time limits, including filing and national phase deadlines.
Educational estimate only. Always confirm deadlines with official WIPO resources and qualified patent counsel for each jurisdiction.
What is a PCT time limit calculator?
A PCT time limit calculator helps inventors, startups, and patent professionals estimate important filing dates under the Patent Cooperation Treaty. The key input is usually your earliest priority date (often the filing date of your first provisional or national application). From that date, many major PCT deadlines are measured in months.
Missing a deadline can be expensive and stressful. A simple calculator gives you a clear timeline so you can plan translation work, local counsel instructions, budgeting, and filing strategy.
Key PCT deadlines you should track
1) 12-month deadline to file your PCT application
In most cases, you have 12 months from your first filing (priority date) to file a PCT application while claiming priority. This is one of the most important dates in your patent strategy.
2) 18-month publication point
International publication generally occurs around 18 months from the priority date. This is when your application becomes publicly visible in many cases.
3) National phase entry deadlines (30 or 31 months)
Most jurisdictions require national phase entry by 30 months from priority, while some allow 31 months. Because each country has specific rules, practitioners often calculate both dates and create reminders ahead of the earliest one.
How to use this calculator
- Enter your earliest valid priority date.
- Select whether you want to plan around a 30-month or 31-month national phase schedule.
- Choose how many days in advance you want a reminder.
- Click Calculate Deadlines.
The tool then displays multiple milestone dates and a status indicator showing whether your selected national phase date is upcoming or already passed.
Practical planning tips
Build in buffer time
Do not wait until the exact deadline. Translation, signatures, assignment issues, and local formalities can create delays. Many teams target completion at least two to four weeks before the legal cutoff.
Track country-specific differences
PCT deadlines are only part of the picture. National laws can vary for restoration of rights, late fees, required forms, and local agent procedures.
Coordinate finance and legal teams early
National phase costs can be significant. Early forecasting helps avoid rushed decisions and preserves strategic flexibility.
Common mistakes to avoid
- Using the wrong priority date from a family chain.
- Assuming every country uses exactly the same time limit.
- Ignoring weekends and local holidays when scheduling internal tasks.
- Waiting too long to begin translations and instructions.
- Relying only on memory instead of maintaining a docket system.
Final note
A PCT deadline calculator is a strong planning aid, but it is not legal advice. For mission-critical filings, always verify dates with official sources and patent counsel in the countries where protection is needed. If used correctly, this tool can reduce deadline risk and make your patent prosecution timeline far more manageable.