01
Naegele's rule estimate
A last period starting 1 January 2026 gives an estimated due date of 8 October 2026, 280 days later.
Pregnancy Due Date Calculator
CalculatorsCalculate your pregnancy due date and how many weeks pregnant you are — free due date calculator.
Uses the standard 280-day (40-week) estimate from Naegele's rule. Your care provider's estimate may differ.
About
About the Pregnancy Due Date Calculator
Estimates a pregnancy due date, conception date and current gestational age from the first day of your last period.
Expecting parents use it for a quick estimate of their due date and how far along they are, while friends and family use it to track roughly when a baby is expected. It's one of many free calculators on Toolapt, and like every tool here, it's free to use with no sign-up and no limit on how many times you run it.
Examples
Pregnancy Due Date Calculator examples
2 worked examples
02
Current gestational age
A last period 12 weeks ago shows a current gestational age of 12 weeks, 0 days.
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FAQ
Frequently asked questions
Quick answers to common questions about the Pregnancy Due Date Calculator.
What does the Pregnancy Due Date Calculator do?
It estimates a due date, conception date and current gestational age from the first day of your last menstrual period, using the standard 280-day estimate.
Is the Pregnancy Due Date Calculator free to use?
Yes. It's free, with no sign-up, no watermark and no limit on how many times you use it.
Is my input safe when I use this tool?
Yes. The date you pick is processed entirely on your own device — nothing is sent to a server.
How accurate is this estimate?
It uses Naegele's rule, a standard 280-day (40-week) estimate widely used as a starting point. Your care provider's estimate, based on an ultrasound or exam, may differ and should be treated as more accurate.
What does "Current gestational age" show if the date is outside a typical range?
It shows a dash (—) if the days elapsed fall outside the usual 0-300 day pregnancy range, since the figure wouldn't be a meaningful gestational age at that point.
What does the estimated conception date mean?
It's estimated as 14 days after the first day of your last period, reflecting a typical ovulation date in a standard cycle — actual conception can vary.
Can I use a date other than today for the last period?
Yes. Pick any past date in the field — "Use today" is just a shortcut for when that date happens to be today.
Can I use the Pregnancy Due Date Calculator on my phone?
Yes. The page is fully responsive and works on mobile, tablet and desktop browsers alike.