This information is for general guidance only.

It does not replace advice from your midwife, GP or healthcare team. Read more about our approach.

When to take a pregnancy test

A home pregnancy test is the first step for many people who suspect they are expecting. Timing matters — test too early and you may get a false negative even if you are pregnant. Use the tool below to work out your earliest and most reliable test dates.

When can I test?

Work out your earliest and most reliable test dates.

How do pregnancy tests work?

Home pregnancy tests detect a hormone called hCG (human chorionic gonadotropin) in your urine. hCG is produced by the placenta from the moment a fertilised egg implants in the wall of your uterus, usually around 6 to 10 days after ovulation.

In the first few weeks of pregnancy, hCG levels roughly double every 48 to 72 hours. That means testing too early gives your body less chance to have produced enough hormone for the test to detect, which is why the most common reason for a false negative is simply testing too soon.

When is the earliest I can test?

Standard tests

From the first day of your missed period

Around 99% accurate on the day of your missed period, when used correctly with first morning urine.

Early response tests

Up to 5 days before missed period

Accuracy drops to around 60 to 76% at 5 days before, rising to 99%+ on the day of your missed period.

After IVF

Your clinic will give you a specific test date

Usually around 14 days after egg collection, rather than transfer. Home testing earlier may pick up hCG from the trigger injection used before collection, which can be misleading. Follow your clinic's instructions.

What affects accuracy?

Testing too early
The most common cause of a false negative. hCG takes time to build up after implantation.
Diluted urine
First morning urine is the most concentrated. Testing later in the day can miss an early pregnancy.
Expired test
Check the expiry date on the box. Expired tests can give unreliable results.
Very early miscarriage or ectopic
A faint positive that fades, or an unusual pattern of symptoms, can indicate a very early loss or ectopic pregnancy. Speak to your GP if you are concerned.
Not following instructions
Every test has specific timing. Reading a result later than the window stated on the leaflet (often 3 to 10 minutes) can cause an evaporation line that looks like a faint positive.

Reading the result

Positive

Two lines (even a very faint second line), or “Pregnant” on a digital test.

Congratulations — see the next section for what to do.

Negative

One line, or “Not Pregnant” on a digital test.

If your period does not arrive, wait 3 days and test again.

Invalid

No lines appear, or the result is unclear.

Test again with a new test, following the leaflet carefully.

I got a positive — what now?

Confirm with a second test (optional)
Some people like to confirm the result with a digital test that shows a clear word, for extra reassurance.
Contact your GP or self-refer to a midwife
In most UK areas you can self-refer directly to your local midwifery service online. You do not always need to see a GP first. Search 'self-refer midwife' and your borough.
Start folic acid 400mcg immediately
If you are not already taking it, start today. Folic acid protects against neural tube defects in the first 12 weeks. See our guide to pregnancy vitamins.
Stop alcohol and review medications
Alcohol is not safe in pregnancy. Check any prescribed or over-the-counter medications with a pharmacist or GP.
Expect your booking appointment around 8-10 weeks
Your midwifery service will arrange your first (booking) appointment, usually between 8 and 10 weeks. This is the longest appointment you will have.

What happens at your booking appointment →Start taking folic acid →Calculate your due date →

Which test should I buy?

Any CE-markedtest sold in a UK pharmacy or supermarket is reliable when used correctly. Digital tests like Clearblue display “Pregnant” or “Not Pregnant” in words, which many people find easier to read, but they are not more accurate.

The cheapest strip tests from Boots, Asda or an online pharmacy are just as accurate as the branded ones. There is very little reason to spend more than £3 to £5 on a test. Buying multipacks is often cheaper per test, which is helpful if you plan to retest.

What about false positives?

False positives from home pregnancy tests are very rare. A positive result is almost always a genuine pregnancy.

Rare causes include:

• Certain fertility medications containing hCG (your clinic will advise)
• A very recent pregnancy loss, where hCG has not yet cleared
• Some rare medical conditions (speak to your GP)

Find your fertile window→ Calculate your due date→ Start taking folic acid→ What happens at your booking appointment→ Early signs of pregnancy→

A note from our team

This guide reflects NHS UK guidance on home pregnancy testing. If your test is positive and you have bleeding, one-sided abdominal pain or shoulder-tip pain, contact your GP or NHS 111 urgently. Read more about us.

Frequently asked questions

How soon can a pregnancy test detect pregnancy?

Most standard home pregnancy tests can detect pregnancy from the first day of your missed period. Early response tests can detect pregnancy up to 5 days before your missed period, but accuracy is lower that early, around 60 to 76% at 5 days before. By the day of your missed period, most tests are over 99% accurate when used correctly.

Can I test before my missed period?

You can, but the result may not be reliable. The hCG hormone that tests detect roughly doubles every 48 to 72 hours in early pregnancy, so testing too early often shows a false negative. If you must test early, use a sensitive early response test with your first morning urine, and retest a few days later if the result is negative.

What does a faint line mean on a pregnancy test?

Any visible second line, no matter how faint, means the test has detected hCG and is almost certainly positive. Faint lines are common in very early pregnancy when hCG is still low. Test again in 48 to 72 hours with your first morning urine. The line should become darker as levels rise.

Are cheap pregnancy tests as accurate as expensive ones?

Yes. Any CE-marked pregnancy test sold in a UK pharmacy or supermarket is reliable when used correctly. Branded digital tests like Clearblue are easier to read but no more accurate than a 99p strip test. You do not need to spend more than a few pounds.

I got a negative but my period hasn't come — what should I do?

Wait 3 days and test again with your first morning urine. Ovulation can happen later than expected, which delays hCG appearing in urine. If you get a second negative and still no period after a week, speak to your GP. They can arrange a blood test and rule out other causes.

Can a pregnancy test be wrong?

False negatives are common, usually because of testing too early or with diluted urine. False positives are extremely rare. Causes of a false positive include certain fertility medications that contain hCG, a very recent pregnancy loss, and rare medical conditions. A positive result is almost always a real pregnancy.