Free tool · Life Events
Pregnancy Due Date Calculator
Use this free due date calculator to estimate a pregnancy due date online.
This free online pregnancy due date calculator estimates your due date in seconds, with no sign-up and nothing saved. Enter the first day of the last menstrual period, or a known conception date, to estimate a due date using the standard 40-week (280-day) method most care providers use. This is a general estimate; your doctor or midwife may adjust it based on an ultrasound or other clinical factors.
- Nothing leaves your device
- Runs entirely in your browser
- Free, no account needed
How to use Pregnancy Due Date Calculator
Two steps, and nothing to install.
Enter your last period or conception date
Type in the first day of your last menstrual period, or a known conception date.
Get your estimated due date
The tool calculates an estimated due date instantly using the standard 40-week method. Nothing is saved or sent anywhere.
More free tools
Free, private, and no sign-up on any of them.
How this works in your browser
The calculation itself is simple date arithmetic - adding 280 days (40 weeks) to the first day of your last period, or 266 days to a known conception date - performed with your browser's built-in JavaScript Date object. Because it runs entirely on your own device, the dates you enter are never transmitted or stored anywhere, which matters for a calculator handling personal health information.
Pregnancy Due Date Calculator vs. typical online calculators
| Feature | Pregnancy Due Date Calculator (in-browser) | Typical online calculators |
|---|---|---|
| Where the maths runs | In your browser, on your device | Often posted to a server to compute |
| Your inputs are stored | Never - nothing is sent or saved | Frequently logged with your session |
| Works offline once loaded | Yes | No - needs a live connection |
| Ads inside the result area | None | Common on free calculators |
| Account required | No | Often, to save or export results |
| Usage limits | None - free, unlimited use | Sometimes capped per day |
Who uses Pregnancy Due Date Calculator
Estimating a due date early
Get a quick estimate as soon as you know your last period or conception date, before your first prenatal appointment.
Planning around a due date
Use the estimate to plan parental leave, travel, or other commitments around the expected timeframe.
Sharing an estimate with family
Quickly work out an approximate due date to share, without needing to look up or remember the standard 40-week calculation.
Frequently asked questions
What it can and cannot do, and what happens to your files.
Is this due date calculator free?
Yes, completely free to use, with no sign-up, and your dates are never saved or sent anywhere.
Is this the same method doctors use?
It uses the standard 280-day (40-week) estimate from the last menstrual period, the same baseline method commonly used, though a care provider may adjust the date based on an ultrasound.
Is this medical advice?
No. This is a general estimate for planning purposes, not medical advice. Follow your care provider’s guidance for your actual due date and prenatal care.
Can I calculate from a known conception date instead?
Yes, the tool supports estimating from either the last period date or a known conception date.
Is there a free pregnancy due date calculator online?
Yes, this calculator is completely free with no sign-up, and the dates you enter are never saved or sent anywhere.
Estimate a due date - free and instant.
Files never leave your device. No upload, no account, and free for unlimited use.