When can I take a pregnancy test?

Enter your last intercourse date or estimated ovulation date.

Last intercourse date

Based on Wilcox 1999. Ovulation and implantation timing vary by ±2–3 days. Learn more
For reference only. This is not a medical diagnosis. For confirmation, see an obstetrician.

How is it calculated?

Test accuracy depends on when hCG production after implantation reaches the test threshold. Per Wilcox 1999, implantation typically happens 8-10 days after ovulation, and hCG becomes detectable in urine 1-2 days later.

Standard sticks (25 mIU/mL sensitivity) reach ≥99% accuracy from 1 week after the missed period. Early-detection sticks (10-20 mIU/mL) can read positive around the expected period day, but with a higher false-negative rate.

Limitations of this estimate

This recommended test day is a reference estimate:

  • If your ovulation day is uncertain (irregular cycles), the recommended test day shifts.
  • Testing too early, dilute urine, or expired strips produce false negatives.
  • hCG injections, recent pregnancy loss (residual hCG for 2-4 weeks), or some tumors cause false positives.
  • Reliability drops while breastfeeding, postpartum, or with PCOS-related hormone shifts.
  • Ectopic pregnancy and biochemical pregnancy cannot be ruled out by a strip — see your OB-GYN.

If negative but your period does not start, retest after 3-5 days or get an OB-GYN blood test.

Sources

Frequently asked

When is the most accurate testing time?

1 week after the missed period is the most accurate window across all OTC strips (near-zero false negatives).

For early indication, 10-20 mIU/mL strips can be used from the expected period day, but a negative result then does not rule out pregnancy. The clinical gold standard is a blood βhCG at the OB-GYN.

Negative test but no period — what now?

The likeliest reason is testing too early (late implantation or late ovulation). Retest with the first morning urine after 3-5 days.

If still negative and your period has not started after 1-2 more weeks, see your OB-GYN for a blood test and to rule out ectopic pregnancy or hormone disorders.