Tracking Your Menstrual Cycle Privately
Overview
A period tracker records the dates of your menstrual cycle so you can see its length, predict upcoming periods, and estimate your fertile window and ovulation. Understanding your cycle helps with planning, spotting irregularities, and knowing your body. This tool keeps your log in your browser on your device — a private space, with none of the sensitive health data uploaded to a server.
How to Use (Step by Step)
- 1
Log each period
Record the start date (and end, if you track it) of each cycle.
- 2
Let it learn your average
Over a few cycles, the tool averages your length to make better predictions.
- 3
See predictions and window
View your predicted next period, fertile window, and estimated ovulation.
How It Works
You log the start (and end) of each period. The tool calculates your cycle length — the days from one period's start to the next — and averages it over time to predict your next period. From that, it estimates the fertile window and ovulation, which typically falls roughly midway through the cycle. Because everything is stored and calculated locally, your reproductive-health data stays on your device.
When to Use This
Predicting when your next period is likely to start. Understanding your average cycle length and how much it varies. Estimating your fertile window when planning or avoiding pregnancy. Spotting an unusually long, short, or missed cycle worth discussing with a doctor. Keeping a private record to share with a healthcare provider. Simply knowing your body's rhythm.
Frequently Asked Questions
They're estimates based on your average cycle, and ovulation timing varies from cycle to cycle. Predictions are more reliable with regular cycles and less so with irregular ones. Don't rely on them alone for contraception.
Important Notes
Predictions are estimates, not medical guarantees — cycle length varies, and fertile-window estimates should not be used alone as birth control. Since data is stored locally, clearing browser data or switching devices can lose your history; back it up. Discuss any concerning changes with a healthcare provider.