Pregnancy Due Date Calculator
Estimate your due date from your last menstrual period.
Result
Results are estimates for general information only and are not professional advice.
Estimating your due date
The most common method (Naegele's rule) adds 280 days — about 40 weeks — to the first day of your last menstrual period. This is an estimate; only about 5% of babies arrive on the exact date. Always confirm with your doctor.
Frequently Asked Questions
What is the Pregnancy Due Date Calculator?
Estimate your due date from your last menstrual period. It runs instantly in your browser and is completely free to use.
What do I need to enter to use the Pregnancy Due Date Calculator?
The Pregnancy Due Date Calculator asks for a single value: First day of last period. Enter it and the result appears immediately — the calculation runs on your own device, so nothing you type is sent to a server.
How accurate is the Pregnancy Due Date Calculator?
The Pregnancy Due Date Calculator uses standard, widely-accepted formulas, so its figures are reliable estimates for everyday planning. They are not a substitute for advice from a qualified professional.
Is the Pregnancy Due Date Calculator free, and do I need an account?
Yes. The Pregnancy Due Date Calculator — and every other calculator on Calculatis — is completely free, with no registration, no download and no limit on how often you use it.