What happens to
what you log.
What period apps do with what you tell them, what the words in a privacy policy actually mean, and how to judge any tracker before you trust it with a year of your life.
Everything under this
The Most Private Period Tracker: What Actually Protects You
Most privacy claims are promises. A few are architecture. This is how to tell which one you are being offered — and the seven questions that separate them.
Read it 9 min read · 7 sourcesWhat Data Do Period Apps Actually Collect?
Three layers of collection, and only one of them is the layer you chose. What a tracker holds, what it works out from that, and what a store privacy label can and cannot prove.
Read it 9 min read · 6 sourcesWho Can See Your Period Data? An Honest Map
Not a name, but a list of routes. The seven ways cycle data can reach somebody else, which of them your app leaves open, and the one that catches almost everybody.
Read it 9 min read · 6 sourcesPeriod Tracker Privacy Check: Judge Any App in Ten Minutes
Six checks, ten minutes, one score out of ten. The drill for judging any period app yourself — and an honest account of what it can and cannot tell you.
Read it 9 min read · 5 sourcesPeriod Tracking Without an App: The Paper Method That Still Works
One date a month, a pen and any calendar is a complete tracking system. Here is what to write down, how to read it back, and where paper genuinely loses.
Read it 9 min read · 7 sourcesHow to Delete Your Period Tracker Data — Properly
Deleting the app is the weakest of the three things people mean by deleting. Here is the order that reaches the copy a company holds, and what the published rules say about how long it takes.
Read it 9 min read · 7 sourcesDoes Deleting the App Delete Your Data? Usually Not
It depends entirely on whether there was an account, and if there was, the answer is no. What uninstalling really removes, and what has to be asked for separately.
Read it 9 min read · 6 sourcesAnonymous Period Tracking: What It Means, and What It Cannot Mean
One word covers three very different promises, and only one of them can be tested from the outside. Here is how to tell which you are being offered.
Read it 9 min read · 6 sourcesOffline Period Tracker vs Cloud Sync: The Honest Trade
Local-only removes the server, the account and the subpoena. It removes the backup with them. Here is the trade, argued against this site's own app.
Read itHow to read these. Every page under this heading links the source of each claim, and every statement about a named app is quoted from that company's own published policy or support page rather than from a review, a memory or a marketing site. Where something cannot be checked, the page says so instead of guessing.
Nothing here is medical advice, none of it is legal advice, and none of it replaces someone who knows your history.
The tools these pages point at
Printable Period Tracker
Build a paper tracker for any month or a whole year, then print it. Flow key, symptoms, an optional temperature row — and a gentler version for a first tracker.
Open itCycle Length Calculator
Log a few period start dates and read your own numbers: average, shortest, longest, and how much the whole thing moves.
Open itPeriod Calculator
Your last period plus your usual cycle length, and the next few months laid out on the moon ring — with the spread you should actually expect.
Open itPrintable Period Symptom Tracker
A month across the top, your symptoms down the side, one box a day. Rename every row, print one page, and bring the pattern to the appointment.
Open itPrintable BBT Chart
Graph paper for a cycle: a temperature grid in °C or °F, a row for the coverline, and space for the notes that make a chart readable later.
Open itAthena keeps all of this on your phone.
The calculators here forget you the moment you close the tab. Athena is the same arithmetic living on your device — the moon ring, an honest calendar with ranges instead of false precision, and a database that never leaves the phone because there is no account and no server behind it.
In development for iPhone and Android. Not released yet — when it is, it will be on this site.
What Athena is