Most home pregnancy tests are reliable from the first day of a missed period. That is when your period would be due: the first day of your last period plus your usual cycle length. Some sensitive tests can show a result a day or a few days earlier, but a negative result that early does not rule out pregnancy. If your period still has not come, test again a few days later.
Why timing matters
Pregnancy tests detect hCG, a hormone your body starts making after a fertilized egg implants in the uterus. Implantation usually happens 6 to 12 days after ovulation. After that, hCG rises over the following days until there is enough in your urine for a test to pick up. Testing too early is the most common reason for a false negative.
How to work out your test day
- Find the first day of your last period.
- Add your usual cycle length, for example 28 or 32 days.
- The result is the day your next period is due: the first reliable day to test.
- A sensitive early test can be tried the day before, but repeat it if it is negative.
Our pregnancy test calculator does this for you and shows both dates.
| Situation | When to test |
|---|---|
| Regular cycle | From the first day of your missed period |
| Irregular cycle | Three weeks after unprotected sex, or after your longest usual cycle |
| You know your ovulation day | From about 14 days after ovulation |
| After emergency contraception | Three weeks after unprotected sex |
If your cycles are irregular
When your cycle length changes from month to month, a missed period is hard to spot. In that case, test three weeks after the last time you had unprotected sex. If you track ovulation signs such as LH tests or basal body temperature, count about 14 days from ovulation instead.
Tips for an accurate result
- Use your first urine of the morning, when hCG is most concentrated, especially if you test early.
- Do not drink large amounts of fluid just before testing.
- Read the result within the time on the instructions; lines that appear later do not count.
- Check the expiry date on the packet.
After a positive or negative result
A positive result is very likely to be correct. Contact a GP, midwife or other healthcare professional to start antenatal care. A negative result is less certain if you tested early: if your period does not start, test again in a few days. If your period is still missing after several negative tests, talk to a healthcare professional.
Get help straight away if you have strong one-sided pain in your lower abdomen, shoulder-tip pain, dizziness or heavy bleeding. If you notice light spotting before your period, our guide on implantation bleeding explains how to tell it apart from a period.
Knowing when your period is due
Bloom Private is a cycle tracker, not a pregnancy app. It estimates when your next period is due from the cycles you log, so you know when a test can give a reliable result. You can also log spotting, LH tests and basal body temperature. The app is not a medical device and cannot tell you whether you are pregnant.
Frequently Asked Questions
Most home tests are reliable from the first day of a missed period. Some sensitive tests can show a result a little earlier, but repeat a negative early test a few days later.
Test three weeks after the last time you had unprotected sex, or about 14 days after ovulation if you track it.
Yes, especially if you test too early, before there is enough hCG in your urine. If your period does not come, test again a few days later.