Pregnancy
Estimate from a starting date.
Copies this page address only, without URL inputs, tracking parameters or a section anchor. It does not share calculation results.
Estimate weeks and a due date from a known starting date.
Choose your last menstrual period, ovulation date, or embryo-transfer date. The result is a calendar estimate, not a clinical record.
This tool cannot say which tests to book, whether a test is complete, or what a result means. Your clinician uses your history, ultrasound, and treatment records to confirm dating and a care plan.
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See the date formulas
| Starting point | Calendar calculation |
|---|---|
| First day of last period | + 280 d |
| Ovulation date | + 266 d |
| IVF transfer date (Day-3 embryo) | + 263 d |
| IVF transfer date (Day-5 blastocyst) | + 261 d |
For a known ovulation date, the week estimate counts that day as 2 weeks 0 days by convention.
This tool no longer creates result links. The copied text includes a reference day, estimated weeks and due date; it is not anonymous or a clinical record. Older shared URLs may still encode your input date. Encoding is not encryption: opening an old link can expose it to recipients and in server requests or logs.
What this calculator can—and cannot—tell you
The conventional estimate adds 280 days to the first day of your last menstrual period. If an ovulation date is known, the estimate adds 266 days to that date and counts it as 2 weeks 0 days pregnant by convention. For IVF, the estimate adds 263 days to a day-3 embryo transfer or 261 days to a day-5 blastocyst transfer. These dating conventions are described in ACOG's methods for estimating the due date.
The output is a calendar estimate, not a diagnosis or your medical record. Period dates may be uncertain and cycle length can vary. A clinician considers your history, an early ultrasound, and any fertility-treatment records when establishing a due date. This site does not tell you which prenatal tests to have, whether they are complete, or how to interpret a result. Discuss those choices with your care team.
Why isn't there an automatic test calendar?
A pregnancy week alone cannot determine an individual's test choices or visit schedule. Earlier versions of this page displayed a fixed timeline and “done” labels without knowing whether a test had actually occurred. We removed those labels rather than implying that a visit was required or completed. Your care team can give you a schedule that fits your history and local healthcare system.
Sharing an estimate
“Copy estimate as text” copies the reference day, estimated weeks and due date—not your starting date or a result link. You can review the text before copying and select it manually if copying fails. These estimates are still health-related information, not anonymous data or a clinical record. Choose who receives them; do not post sensitive information publicly.
Older shared URLs may still encode a pregnancy or treatment date. Encoding is not encryption. Opening an old link can reveal that date to recipients and in server requests or logs. This change cannot remove copies or logs that already exist.
Result-copy behavior updated 2026-10-10. Medical sources reviewed 2026-09-27. Educational date calculation only; not a substitute for medical advice. Confirm your due date, symptoms, tests, and care plan with a qualified clinician.