ran cycle tracker, 2026

How to install

iPhone or iPadOpen the link in Safari, tap Share, then Add to Home Screen.
AndroidOpen the link in Chrome, tap ⋮, then Install app.
ComputerOpen the link in Chrome or Edge, then click the install icon in the address bar.

Ran is a menstrual cycle tracker for people who already know the underpinnings of their menstrual cycles.

A sample cycle, in °F. Temperature rises after ovulation. The red line, called the coverline, sits just above the six days before the rise, and three days above it confirm ovulation. P marks Peak Day. Soon you'll be able to drag the dots around.

A few years ago, I read Taking Charge of Your Fertility by Toni Weschler. It taught me how the menstrual cycle actually works, the biology behind ovulation, basal body temperature, follicular phases, how to know when you are ovulating. Did you know that some female mammals are only fertile one day a year? The males somehow know when to get in action. Nature is wondrous. All the signs are already within you. You just need to learn to attune to them.

For years, I tracked my cycles with the app that accompanied the book. Then the app was discontinued, and all my data disappeared with it.

I tried several popular cycle-tracking apps after that. None quite worked for me. Most are designed to work like a black box. They assume very little knowledge from the users.

So I built Ran, exactly how I like it.

Ran focuses on the information I actually care about. It tracks indicators like average follicular-phase length, which helps me see how stress affects when I ovulate. Visually, it provides a BBT chart for spotting temperature shifts, and a cycle-length chart for seeing patterns over time.

It also works offline. Users own the data. You can export everything as CSV or JSON.

And then there is perhaps the app's most practical feature.

Every time I go to the doctor's office, someone invariably asks:

When was your last period?

For some reason, this is the one piece of information my brain refuses to retain.

So I put Last Period right smack in the center. Now I almost look forward to the question.

Almost.