When to take a pregnancy test: find your most accurate day
Most accurate test from: Saturday, October 24
That’s the day your period is due. Some sensitive tests can show a result a few days earlier (from about Tue, Oct 20), but a negative before your missed period isn’t reliable. Test with your first morning pee, and again in a few days if your period still hasn’t come.
🔒 Calculated in your browser. Nothing you type is sent or stored. Estimates only: cycles vary.
Take a pregnancy test from the first day of your missed period: that's when most home tests are reliable. Some sensitive tests can pick up pregnancy a few days earlier, roughly 10 days after ovulation, but a negative result that early isn't trustworthy. If you don't know when your period is due, test at least 21 days after unprotected sex.
How the test date calculator works
Enter the first day of your last period and your usual cycle length. The calculator finds the day your next period is due, which is the most accurate day to test. It also estimates ovulation (about 14 days before that period) and shows the earliest day a sensitive test might work, about 10 days after ovulation.
Calculated in your browser, nothing stored. If your cycles are irregular, the due date is less certain: use the 21-days-after-sex rule instead.
Why timing matters
Home tests detect hCG, a hormone made once a fertilized egg implants in the lining of the uterus. Implantation usually happens 8 to 10 days after ovulation (the implantation calculator shows your window), and hCG then roughly doubles every couple of days. Test too early and there may not be enough to show, even if you are pregnant.
| When you test | How reliable a result is |
|---|---|
| Less than 9 days after ovulation | Too early: hCG is usually not there yet |
| 10 to 13 days after ovulation | Some sensitive tests may show a positive; a negative means little |
| Day your period is due | Most home tests are reliable from here |
| A few days after a missed period | Very reliable; retest if still negative and no period |
| 21 days after unprotected sex | Reliable even if you don't know your cycle |
Tips for an accurate result
- Read the leaflet. Tests differ in sensitivity and in how long to wait before reading.
- Any time of day works for most tests, but first morning urine is the most concentrated, which helps if you're testing early.
- Don't drink lots of water first. Diluted urine can make an early test look negative.
- A faint line usually counts as positive if it appears within the reading time. Retest in two days to see it darken.
- A negative but no period? Wait two or three days and test again. Ovulation may have been later than you thought.
PMS or pregnancy?
The two-week wait is hard partly because early pregnancy and PMS feel so alike: sore breasts, tiredness, cramps, bloating and mood swings can be either. Progesterone drives both. The only reliable way to tell is a test after your missed period. See PMS vs pregnancy symptoms and implantation bleeding vs a period.
Waiting can also bring anxiety, and anxiety itself can delay ovulation in the next cycle. If the wait is getting to you, it's okay to plan a distraction for the days before your test date.
When to talk to a doctor
Get urgent help if you have a positive test with one-sided belly pain, shoulder-tip pain, dizziness or heavy bleeding, as these can be signs of an ectopic pregnancy. See a doctor if your period is still missing after two negative tests a week apart, or if you've missed three periods.
Frequently asked questions
How soon can I take a pregnancy test?
Some sensitive tests can show a positive around 10 to 12 days after ovulation. For a result you can trust, wait until the day your period is due.
Can a pregnancy test be negative and you still be pregnant?
Yes, if you test too early or with diluted urine. If your period doesn't come, test again in a few days.
How long after sex can I take a test?
If you don't know when your period is due, wait at least 21 days after unprotected sex.
Does the time of day matter?
Most tests work any time of day. First morning urine helps most when testing before a missed period.
Sources
- NHS: Doing a pregnancy test
- Wilcox AJ et al. Time of implantation of the conceptus and loss of pregnancy. NEJM (1999)
- NHS: Signs and symptoms of pregnancy
This page is for information only and isn’t medical advice. If something worries you, please talk to a doctor.
Keep reading
Implantation calculator: when does implantation happen?Free implantation calculator: see the days implantation would most likely happen this cycle, what implantation bleeding looks like, and when to test.
How late is my period? Check in secondsHow late is my period? Enter your last period and cycle length to see exactly how many days late you are, whether that's normal, and what to do next.When should you take a pregnancy test?How soon can you take a pregnancy test? Most work from the first day of a missed period. When early tests work, best time of day, and when to test again.Late period but a negative pregnancy test?Late period but a negative pregnancy test? You may have tested early or ovulated late. Other common causes, when to retest, and when to see a doctor.PMS or pregnancy? How to tell the differencePMS vs pregnancy symptoms look almost the same: sore breasts, cramps, tiredness, mood swings. The few clues that differ, and when a test is reliable.