6 Best Period Trackers for Irregular Cycles (2026)

Irregular cycles break apps that assume a tidy 28-day month. If your period arrives on its own schedule (or barely arrives), you need a tracker that treats irregularity as normal, not a bug.

This list mixes PCOS-aware tools and careful general trackers. Forecast quality varies. Treat any “due in X days” line as a guide, not a medical claim. Prices are approximate; verify in store.

Disclosure: we make PCOS: Symptom & Period Tracker.

Quick Comparison

• PCOS: Symptom & Period Tracker — Assumes irregular cycles; free logging; Premium simple on-device estimates. About $6.99/mo or $39.99/yr.

• Cysterly — PCOS-oriented tracking. Premium often about $9.99/mo or $34.99/yr.

• Clue — Flexible logging; still a general cycle model. Clue Plus often about $9.99/mo or $39.99/yr.

• Flo — Popular forecasts; can feel wrong on long or chaotic cycles. Premium often about $9.99–$14.99/mo or $39.99–$59.99/yr.

• Natural Cycles — Fertility / contraception positioning (thermometer). Different job than PCOS symptom logging. Pricing varies; check store.

• Glow — Fertility and cycle logging with a broader wellness feel. Pricing varies by plan; check store.

1. PCOS: Symptom & Period Tracker

Designed so irregular cycles are the default story. Log flow and cycle marks without pretending every month looks the same. Premium forecasts are simple on-device estimates from what you logged, not a forced fertility calendar. Logging stays free forever.

Best for: PCOS and irregular cycles when privacy and free write-logging matter most.

Start here: Learn more · Google Play · App Store

2. Cysterly

A PCOS-specific peer focused on symptoms and reports. Useful when irregularity and PCOS symptoms travel together. Compare Premium gates and reviews as the app is newer.

Best for: people comparing dedicated PCOS trackers for uneven cycles.

3. Clue

Clue is often praised for a calmer, research-leaning tone. You can log messy cycles, but the product still serves a general audience. Good if you like Clue’s UI and accept that PCOS is not the center of the roadmap.

Best for: irregular cycles inside a mainstream science-forward tracker.

4. Flo

Flo’s predictions are a big part of the brand. For irregular cycles, that strength can become the frustration: optimistic forecasts that miss. Still a capable logbook with lots of content if you ignore the calendar pressure.

Best for: users who want Flo’s content and can take forecasts with skepticism.

5. Natural Cycles

Built around fertility awareness with temperature input. Powerful for its intended use. It is not a PCOS symptom diary. Include it only if your goal is fertility/contraception tracking, not hirsutism and visit prep.

Best for: people whose primary job is fertility awareness, not PCOS symptom history.

6. Glow

Glow covers periods, fertility, and related logging with a community/history that many still recognize. Feature sets and paywalls shift over time. Check whether your irregular-cycle needs are first-class before paying.

Best for: users who want a fertility-leaning general app and will verify current pricing in store.

How to choose

If irregular cycles are the whole point, prefer apps that say so up front. If you only need a blank log, Clue or Flo can work. If you want PCOS symptoms plus free forever logging, start with PCOS: Symptom & Period Tracker.