Free sexual health tools
Practical calculators for the questions that need a date, not an article. Each one runs entirely in your browser — nothing you enter is stored, sent, or shared.
Ovulation & Fertile Window Calculator
Estimate your ovulation date and fertile window from your last period and average cycle length.
Open toolSTI Testing Window Calculator
See the earliest reliable and conclusive test dates for each STI, counted from a possible exposure.
Open toolBirth Control Method Finder
Answer five questions to narrow down which contraceptive methods are worth discussing with a provider.
Open tool
Why these run in your browser
Sexual health questions are personal, and a tool that asks when you were exposed to an infection or when your last period started is asking for genuinely sensitive information. So none of it goes anywhere. There is no submit button, no server call, and no analytics event attached to what you type. You can disconnect from the internet after a page loads and the calculator still works.
None of these tools diagnose anything. They convert dates into other dates, or narrow a list of options — the kind of arithmetic that is tedious by hand and easy to get wrong. What you do with the result belongs in a conversation with a healthcare provider.