Work out your due date
Nothing you enter leaves this page. Niva does not store it, send it or measure it.
How the date is worked out
| You start from | Days added | Where the number comes from |
|---|---|---|
| First day of your last period | 280 days (40 weeks) | ACOG: "By convention, the EDD is 280 days after the first day of the LMP." |
| IVF, day-5 embryo transfer | 261 days | ACOG: 261 days from the transfer of a day-5 embryo |
| IVF, day-3 embryo transfer | 263 days | ACOG: 263 days from the transfer of a day-3 embryo |
| Conception date | 266 days (38 weeks) | The 280-day method assumes about 14 days between the period start and ovulation, so 280 minus 14 |
The 280-day count assumes a regular 28-day cycle. If your cycles are longer, shorter or irregular, or you are not sure of the date, the estimate can be off. ACOG notes that an ultrasound in the first trimester is the most accurate way to set or confirm the dates, so the date your care team gives you may be different.
Source: ACOG Committee Opinion 700, Methods for Estimating the Due Date.
A note on dates
Educational wellness support, not medical advice. Your care team confirms your dates and what fits your pregnancy.
Questions people ask
How is a due date calculated?
The usual method adds 280 days, or 40 weeks, to the first day of your last period. This calculator does the same, and ACOG describes it as the convention.
How do I work out my due date after IVF?
ACOG counts 261 days from a day-5 embryo transfer and 263 days from a day-3 embryo transfer. Pick the IVF option above that matches your transfer.
Can my due date change?
Yes. Your care team may set a different date, for example after an ultrasound in the first trimester, which ACOG notes is the most accurate way to set or confirm the dates.
Does Niva keep the date I enter?
No. The calculator runs in your browser. Nothing you enter is sent, stored or measured.
