When should I test after sex?

Enter the date of the exposure. We'll show when each test can find an infection, based on CDC guidance, and when a negative result is most reliable.

The date stays on this device. We don't send, save or log it.

Medical review pendingWritten by the STD Test Prices editorial team using CDC sourcesLast updated Oct 30, 2026

Date of the exposure

Use the most recent date that concerns you.

Already treated? When to retest

Chlamydia and gonorrhea: about 3 months after treatment, whether or not you think your partners were treated. Don't retest for chlamydia sooner than 4 weeks after treatment, because the test can pick up leftover dead bacteria.
Gonorrhea in the throat: a test of cure 7 to 14 days after treatment.
Trichomoniasis: women should retest about 3 months after treatment.
Syphilis: follow-up blood tests at 6 and 12 months after treatment for primary or secondary syphilis.

How this works

Each date is the exposure date plus the number of days CDC gives for that test. Where CDC doesn't publish an exact window, as for chlamydia, gonorrhea and trichomoniasis, we use the timing in CDC's guidance for repeat testing after a sexual assault: 1 to 2 weeks for these infections, 4 to 6 weeks and 3 months for syphilis, and 6 weeks and 3 months for HIV. Your date never leaves this device.

This calculator gives general timing based on CDC guidance. It isn't medical advice and doesn't replace a clinician. Window periods are typical ranges, and a few people take longer to test positive. If you have symptoms, see a clinician now. If you were sexually assaulted, the RAINN National Sexual Assault Hotline is available any time: call 800.656.HOPE or text HOPE to 64673.

Already treated? When to retest

Sources