Pregnancy Test Calculator: when can I take a pregnancy test?

Calculate implantation and your test day from your period, ovulation, LH test, or the day you had sex, with a reminder in your phone calendar

Runs only in your browser, nothing is stored

What do you know?

The first day with real bleeding, not spotting.

Calculate more precisely optional

The luteal phase is the time from ovulation to your next period. Your test’s sensitivity is printed on the box or in the package leaflet.

Note: The Pregnancy Test Calculator is a general calendar estimate for information only. It does not make a diagnosis and does not replace a test or a medical examination.

Updated on 25 October 2026 · Fertilio Editorial Team

A urine pregnancy test is reliable from the day your period would be due. An early pregnancy test with 10 mIU/ml can turn positive about 10 days after ovulation, but in many pregnancies only later. The calculator shows you both days, plus the implantation window and when a blood test starts to give a meaningful result.

How the Pregnancy Test Calculator works

The starting point is always ovulation. The calculator determines it from what you know:

  • Last period: By calculation, ovulation falls about 14 days before the next period, so around cycle day 14 with a cycle length of 28 days. Because ovulation varies from cycle to cycle in the same woman, in this case the calculator aligns all test days with the day your period is due.
  • Ovulation known: for example from ultrasound, basal body temperature, or a fertility tracker. The calculator sets your expected period 14 days later; under “Calculate more precisely,” you can set your own luteal phase.
  • Positive LH test: The rise of the hormone LH in urine comes, on average, just under one day before ovulation. The calculator takes the day after the first positive ovulation test as the day of ovulation.
  • Day you had sex: You can only get pregnant if ovulation happened on the day you had sex or in the 5 days after. The calculator therefore shows the earliest test day for ovulation on the same day and the reliable test day for the latest case.

The calculation runs only in your browser. Fertilio does not store any of your information.

When to take a pregnancy test: the days at a glance

A test measures the pregnancy hormone hCG. The body only produces it once the fertilized egg has implanted. After that, the level in urine roughly doubles every one and a half to two days during the first days.

Timing What a test can show
up to 8 days after ovulation No test turns positive, even if you are pregnant.
9 days after ovulation Only rarely positive; the hCG level averages 4 mIU/ml.
10 days after ovulation An early test with 10 mIU/ml can turn positive, in about one in two pregnancies.
11 to 12 days after ovulation A standard test with 25 mIU/ml can also turn positive.
Day of the expected period A urine test is reliable. If it stays negative but your period does not come, test again after 3 days.

The values for hCG in urine come from measurements in 109 women, counted from ovulation. On day 10, the average value was 12 mIU/ml, on day 11 it was 25 mIU/ml, and on day 14 it was 137 mIU/ml.

Calculating implantation: when does the egg implant?

The fertilized egg implants in the lining of the uterus 6 to 12 days after ovulation. In a study with regular urine samples, this happened on day 8, 9, or 10 in 84% of pregnancies. hCG can only be detected from implantation onward.

The later the implantation, the more often the pregnancy ended early: with implantation by day 9 in 13% of cases, on day 10 in 26%, and on day 11 in 52%. Implantation cannot be reliably felt. Light bleeding around this time does happen, but it is not a sure sign.

After an embryo transfer, different days apply because the embryo is already a few days old. The test days after fertility treatment are shown in the IVF section of the Due Date Calculator, and you can read more about implantation after the transfer in the guide on frozen embryo transfer.

Early test or standard test: 10 or 25 mIU/ml?

The package states the amount of hCG at which a test turns positive. Early tests are at 10 mIU/ml, standard tests usually at 20 to 25 mIU/ml. The lower the number, the earlier the test can turn positive.

  • Early test (10 mIU/ml): 10 days after ovulation at the earliest, or about 4 days before your expected period if you do not know when you ovulated. Manufacturers advertise “up to 6 days before your missed period.” According to their own laboratory data, they detect just under 80% of pregnancies on this earliest day.
  • Standard test (25 mIU/ml): 11 days after ovulation at the earliest, or about 3 days before your expected period, and reliable from the day of your expected period.

Two limitations: Not every test reaches the sensitivity stated on the package. In an evaluation of 9 tests from German pharmacies, about half did not. And even an ideal test detects only about 90% of pregnancies on the day of the expected period, because some eggs implant late. One week later, it is 97%.

For an early test, it is best to use first morning urine and not to drink much beforehand. From the day of your expected period, any time of day is fine. Which tests have which detection limit and what they cost is shown in the pregnancy test comparison.

1 to 14 DPO: day by day

DPO stands for days past ovulation, so 7 DPO means 7 days after ovulation. Many people in forums count this way because it is more precise than the cycle day.

Day What happens hCG in urine (average)
1 to 5 DPO The fertilized egg travels through the fallopian tube to the uterus. not measurable
6 DPO Earliest implantation. not measurable
7 DPO Implantation possible, test still negative. 0 mIU/ml
8 DPO The most common implantation days begin. 0.1 mIU/ml
9 DPO Implantation in many pregnancies, test almost always still negative. 4 mIU/ml
10 DPO An early test with 10 mIU/ml can be positive. 12 mIU/ml
11 DPO A standard test with 25 mIU/ml can be positive, blood test gives a meaningful result. 25 mIU/ml
12 DPO Latest usual implantation. 48 mIU/ml
13 DPO Most early tests are positive if you are pregnant. 75 mIU/ml
14 DPO Period due, urine test reliable. 137 mIU/ml

These values are averages. Individual women have values well above or below these, so a negative test before your expected period does not rule out pregnancy.

Blood test at your gynecologist

A blood test measures hCG in the blood and can give the exact amount. Around 9 to 10 days after ovulation, the level is about 10 mIU/ml. Depending on the laboratory, a level of 25 or 30 mIU/ml or higher counts as positive, and a level below 5 mIU/ml as not pregnant. A blood test is therefore meaningful from about day 11 after ovulation. If the level is in between, the test is repeated after 2 to 3 days.

Negative test, no period

The most common reason for a false negative result is testing too early. Often ovulation was later than you thought, and so was your period. Repeat the test after 3 days, again with first morning urine. If it is still negative one week after your expected period and your period still does not come, have the cause checked by a gynecologist.

A positive test that is soon followed by bleeding can be a chemical pregnancy. About one in four to one in five implantations ends this early, and many of them would not even be noticed without an early test.

A test can give a false positive result after an hCG injection, such as the trigger shot used in fertility treatment to induce ovulation. According to the summary of product characteristics of one such medication, it can interfere with the measurement for up to 10 days.

Frequently asked questions

When can I take a pregnancy test?

Reliably from the day your period would be due. An early test with 10 mIU/ml can turn positive about 10 days after ovulation, a standard test with 25 mIU/ml from about day 11. Before that, a negative result does not give you an answer.

How many days after sex can I test?

At the earliest 10 days after, and only if ovulation happened on the day you had sex. Because sperm survive for several days, ovulation may have been up to 5 days later. A test is therefore only reliable 19 days after sex or from the day of your expected period.

When does the fertilized egg implant?

6 to 12 days after ovulation, usually on days 8 to 10. Only then does the body produce hCG, which a test can measure.

How reliable is an early test?

A positive result is usually correct. A negative result before the day of your expected period, on the other hand, means little, because the hCG level may still be too low. The detection rates on the package come from the manufacturers’ laboratory tests.

Is first morning urine better?

For an early test, yes, because first morning urine contains more hCG during pregnancy. Manufacturers and the US Food and Drug Administration (FDA) recommend this. From the day of your expected period, you can test at any time of day.

When does a blood test show a pregnancy?

From about day 11 after ovulation, so a few days earlier than a standard urine test. The blood test is done at your gynecologist’s practice.

Does Fertilio store my information?

No. The calculator calculates only in your browser. For the calendar file, the calculated dates are sent once to our server, converted into a file there, and not stored.

Sources