Pregnancy Due Date Calculator
Work out an estimated due date, and see how far along you are today.
Pregnancy Due Date Calculator
Estimated due date
25 May 2027
- How far along you are8 weeks 4 days
- TrimesterFirst trimester
- Likely conception date1 September 2026
- Days to go220
Works out in your browser. Nothing you type is sent anywhere.
In short: Pregnancy Due Date Calculator
From the date entered, the estimated due date is 22 May 2027, which is 220 days away. You would be 8 weeks 4 days along today, which falls in the First trimester, and conception would have been around 29 August 2026. A scan dates a pregnancy more accurately than any calendar.
What is Pregnancy Due Date?
An estimated due date is forty weeks from the first day of the last period, adjusted where the cycle is not twenty-eight days long.
How is Pregnancy Due Date calculated?
Naegele's rule adds forty weeks to the first day of the last period. Where the cycle is longer or shorter than twenty-eight days, ovulation happened later or earlier, so the difference is added. Counting from conception instead uses thirty-eight weeks.
- EDDthe estimated due date
- LMPthe first day of the last menstrual period
- cyclethe usual cycle length in days
A worked example
| Work it out from | First day of the last period |
|---|---|
| That date | 15 August 2026 |
| Usual cycle length (days) | 28 |
| Result | |
| Estimated due date | 22 May 2027 |
| How far along you are | 8 weeks 4 days |
| Trimester | First trimester |
| Likely conception date | 29 August 2026 |
| Days to go | 220 |
Every figure in this table is produced by the same calculation the tool above runs.
How to use this pregnancy due date calculator
- Choose whether you are counting from the last period or from conception.
- Enter that date.
- Enter your usual cycle length, which adjusts the estimate.
- Read the due date, and how far along you are today.
Questions people ask
How accurate is an estimated due date?
Only a small share of babies arrive on the estimated date, and anywhere in the two weeks either side is considered normal. The estimate is used to plan care, not to predict the day. An early scan dates a pregnancy more accurately than any calculation from dates.
Why is pregnancy counted from the last period?
Because the first day of the last period is a date most people know, while the day of conception usually is not. It means the first two weeks of the forty are counted before conception actually happened. That is why counting from conception uses thirty-eight weeks instead.
What if my cycle is not twenty-eight days?
The estimate is adjusted for it, because a longer cycle means ovulation happened later and the due date moves back accordingly. Entering your real cycle length matters most for cycles well away from twenty-eight days. For very irregular cycles, a scan is the reliable answer.
Is anything I type here saved or shared?
No. Everything is worked out inside your browser, nothing is stored, and this tool will not put your dates into a link or an image. Only the page's own address can be shared.
Accuracy and sources
For general information. Not medical advice.
Checked by the Daytoolz team on 16 October 2026. How we check our tools.
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