STI Testing Date Guide

When to test for chlamydia, HIV, syphilis and more. Free, private and instant.

How to use the STI Testing Guide

  1. Pick date of possible exposure.
  2. Choose do you have symptoms now?: No symptoms or Yes (discharge, sores, pain, rash, itching).
  3. Press Calculate to get an instant result with a colour scale, chart and plain-English explanation.

About the STI Testing Guide

Different infections show up on tests at different times after exposure. Enter the date and see when to test for each infection, when a result is reliable and whether urgent post-exposure treatment (PEP) is still possible.

Also known as: STD test window period, when to get tested for STI, STI window period calculator, HIV test window.

Worked example

Dates in this example are worked out as if today were 5 Nov 2026.

Days since exposure: 10 days (Too early for most tests). 10 days have passed since 26 Oct 2026. Some tests are ready now, others should wait. See the timeline below.

Formula and cut-offs

Typical test windows (days after exposure): chlamydia and gonorrhoea 14, trichomoniasis 28, syphilis 90, HIV 4th-generation lab test 45, hepatitis B 84, hepatitis C 84, herpes antibodies 112.

Frequently asked questions

How soon after sex can I get tested for STIs?

Chlamydia and gonorrhoea from about 1 to 2 weeks; HIV about 4 to 6 weeks; syphilis up to 3 months for a fully reliable result.

What is HIV PEP?

Post-exposure prophylaxis is emergency HIV medicine that must be started within 72 hours of a possible exposure.

Should I test if I have no symptoms?

Yes. Many STIs cause no symptoms but can still be passed on or cause harm.

Sources and references

Written and checked by the MediHub editorial team against the sources above. Read how we build and review our calculators.

More health calculators

Last updated . This calculator is for education only and is not medical advice. See the medical disclaimer.