Cycle Tracker
Track menstrual cycles by start and end date.
Overview
The Cycle Tracker is a simple, private log of menstrual cycles recorded by start and end date. Each entry contributes to a running average cycle length and period length, and the tracker projects the next likely start date based on your recent history. There are no ads, no targeted promotions, no third-party sharing, and no behavioural inferences sold to a data broker, all of which matter in a category that has come under deserved scrutiny.
The use case is honest and narrow: knowing roughly when the next period is due, spotting changes in cycle length over time, and having a clean record to bring to a GP, gynaecologist, or fertility specialist when needed. Because entries are plain dates rather than fertility predictions or contraceptive guidance, the tool stays inside its lane and leaves clinical interpretation to qualified professionals.
How it works
You add a cycle with a start date and an end date. The tracker calculates the period length and the cycle length, defined as the gap from one start date to the next. After a few cycles, average and median lengths appear, alongside a projection of the next expected start.
Data is stored locally in your browser. You can edit a date you got wrong, remove an entry, and export or copy the list as plain text to share with a clinician.
Examples
- Logging a 5-day period starting on the 3rd of the month, contributing to a running 28-day cycle average.
- Tracking a slightly longer 32-day cycle and noticing it correlated with a high-stress month.
- Recording a 3-day light period after a change in contraception, noted in a free-text field.
- Bringing a six-month history to a fertility consultation, neatly listed and ready to print.
FAQ
Is my cycle data private?
Entries stay in your browser's local storage. Nothing is sent anywhere or shared with third parties.
Does it predict ovulation or fertile windows?
No. It tracks period dates and cycle length only. Fertility prediction requires more inputs and is best done with a clinically validated method.
What if my cycle is irregular?
The tracker still records every cycle. The averages will show the variability, which is itself useful clinical information.
Can I export the data?
Yes. The entry list can be copied as plain text for use in messages, documents, or print-outs.
Does it cover pregnancy or post-partum tracking?
Not directly. You can leave gaps in the history during those periods and resume logging when cycles return.