Choosing a period tracker,
without the marketing.
Head-to-head reading on the apps people actually search for, on the two the phone already ships with, and on paper. Every statement about a named app comes from that company's own policy, and where nothing can be verified the page says so instead of guessing.
Everything under this
Flo Alternatives: Honest Options, Including the Ones That Are Not Apps
People leave Flo for four different reasons, and each one points at a different replacement. Here is the honest field, described only from what each company publishes about itself.
Read it 9 min read · 6 sourcesClue Alternative: What Changes If You Switch
Clue publishes a comparatively strict position on your data, so the useful question is what a move would actually gain you. Three real reasons to switch, what each one costs, and how to go without losing your history.
Read it 9 min read · 6 sourcesFlo vs Clue: What Each One Publishes About Your Data
A head-to-head built only from published, checkable statements. It compares documents rather than experiences, marks the questions neither company answers, and does not pick a winner.
Read it 8 min read · 5 sourcesApple Cycle Tracking: What the Health App Does, and What It Does Not
The period tracker already on your iPhone, judged on what Apple publishes about it. What it logs, what it predicts, what the deviation alert means — and the two things it cannot do for anyone.
Read it 9 min read · 6 sourcesPeriod Tracker Without an Account: What to Look For
An account is the mechanism by which your cycle data comes to live somewhere other than your phone. How to tell whether an app has one, and what going without honestly costs you.
Read it 9 min read · 6 sourcesPeriod Tracker Without a Subscription: What Free Actually Costs
Every way of funding an app leaves a fingerprint on the product. Here are the five ways a period tracker gets paid for, and how to work out which one is paying for yours.
Read it 8 min read · 6 sourcesPeriod Tracker Without Ads: Why the Business Model Is the Feature
An advert has to be aimed, and aiming it is what gives your data a reason to travel. How to read the store labels, and what "no ads" does and does not cover.
Read it 8 min read · 7 sourcesThe Best Period Tracker for Teens: A Privacy-First Answer
Early cycles are irregular for years, so a first tracker's job is memory, not prediction. Here is what to look for, what the store labels actually mean, and a short section for the parent reading over a shoulder.
Read it 8 min read · 6 sourcesOpen Source Period Trackers: What Being Open Actually Buys You
Open source turns a privacy promise into something somebody can check. That is worth a lot, and it is not proof — here is exactly where the line falls, and what drip and Euki actually say about themselves.
Read it 7 min read · 6 sourcesPaper vs App Period Tracking: An Honest Comparison
A notebook and a phone fail in different places. Compared on the axes that matter, with an honest verdict and the readers for whom paper alone is the better answer.
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
Period 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 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 itPrintable 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 Phase Calculator
Which phase you are probably in today, what is actually happening in it, and a straight answer about how blurred the edges between them are.
Open itFirst Period Kit Checklist
What to put in a school bag and what to keep at home, on one printable page. Editable, unfussy, and written to be reassuring rather than dramatic.
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