Pregnancy & baby calculators
6 free tools
The dates and numbers that come up the moment two lines show up on a test. Work out when conception likely happened, what week you're in today, how a due date maps back to your last period, and roughly what that first year of diapers and daycare adds up to.
Estimate what a baby's first year will actually cost by adding up diapers, formula, childcare, gear, and the rest.
Estimate the day you most likely conceived from your due date or the first day of your last period.
Get your due date from an IVF transfer date, with the right offset for a 3-day or 5-day embryo transfer.
Count down to your due date with the weeks and days left and a friendly progress readout.
See how far along you are in weeks and trimester, from your last period or a known due date.
Work backwards from a due date to the estimated conception window and the date of your last period.
Frequently asked questions
How are pregnancy due dates calculated?
The standard rule (Naegele's rule) adds 280 days — 40 weeks — to the first day of your last menstrual period. That assumes a regular 28-day cycle, so an early ultrasound often adjusts the date a little.
Why is pregnancy counted from the last period, not conception?
Most people know when their last period started but not the exact day they conceived. Counting from the last period gives a consistent starting line, which is why you're technically 'two weeks pregnant' before conception even happens.
Are these calculators a substitute for a doctor?
No — they're quick estimates to help you plan. Ultrasound dating and your provider's guidance are what actually matter, especially if your cycle is irregular or you're using IVF.