Flo vs Clue: Which Period Tracker Is Better?

This Flo vs Clue page is a two-product decision after both apps exist as cycle diaries. This is a source-reviewed guide, not a hands-on lab test. Apple, Play, help pages and named public records were captured on 13 September 2026. We did not log the same cycle in both apps.

Flo vs Clue at a glance

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Download Clue Period & Cycle Tracker on the App Store · Get Clue Period & Cycle Tracker on Google Play

Pick Flo if you want a large community, partner sharing, and a published Anonymous Mode after a 2021 enforcement case you have actually read. Pick Clue if you want a women-led Berlin app, EU server copy, and you will pay or ignore Clue Plus. That is the whole decision rule. This page does not add a third brand.

How each app describes itself

Flo’s US Apple page, captured 13 September 2026, listed 70-plus symptoms, BBT tools, pregnancy week-by-week, a Perimenopause Score, Secret Chats, Flo for Partners, and Premium courses plus a Symptom Checker. The Symptom Checker is marked unavailable in the UK and EU.

Clue’s US Apple page listed 200-plus symptoms, life-stage modes, 400-plus articles, and wearable links including Oura, WHOOP, Withings and Fitbit. Clue Plus support (12 January 2026) adds 12-month forecasts, BBT charts and Connect. Apple marked Conceive mode as a medical-device aid for conception — not contraception.

Both print a disclaimer: not a method of birth control. For the wider field, use best period tracker apps.

Flo vs Clue price

Flo does not publish one global Premium rate. The US IAP grid mixed $1.99, $7.49, $14.99, $47.99 and $59.99 Premium rows plus other named products. If $59.99 is annual, the year costs $59.99. If $14.99 is monthly, twelve bills cost $179.88. A $1.99 row might be weekly. We will not guess. Flo help says most offers include a one-time trial that converts unless you cancel in the store.

UK Flo Premium rows included £39.99, £35.49, £16.99, £14.99 and £11.99. A GB listing review said the writer was charged about £43 after thinking they had picked monthly. That is one checkout story, not our purchase.

Clue’s grid is simpler: US $9.99 a month or $39.99 a year; UK £7.99 a month or £23.99–£24.99 a year. Twelve monthly payments cost more than the named year in both countries. Clue’s Plus cost article (12 January 2026) says the live number follows the store region. Ownership over 24 or 36 months is the same auto-renewing SKU multiplied. Open both paywalls on the same day.

Ratings are not a quality score

Flo’s US Apple pile is 4.7 from 2 million ratings. Clue’s is 4.8 from 403,000. On Play the volume gap is wider: Flo about 5 million reviews at 4.7; Clue about 1.5 million at 4.5. UK Apple sits closer (295,000 vs 110,000) at 4.7 each.

Featured Flo Play notes from 2024–2025 said useful tools moved behind Premium. Featured Clue Play notes from 2025 said Plus banners fired after every action. Those are dated sentiment snapshots, not lab scores. Flo’s download claims (500 million on Apple, 570 million on Play) and Clue’s “100M” Play line are manufacturer figures, not an audit.

Privacy and past enforcement

The US Federal Trade Commission finalized an order against Flo Health, Inc. on 22 June 2021. The complaint alleged that Flo shared health analytics with firms including Facebook and Google after promising privacy. The order required notice, deletion instructions, consent before sharing health information, and an independent review. Flo’s public response says it stopped that sharing in January 2021, did not admit wrongdoing, and later pointed to a March 2022 Guidepost audit plus ISO 27001 and 27701 certificates. 2026 store copy repeats those ISO lines and Anonymous Mode.

That history is not a 2026 leak. It is a reason to read the live Apple label. On the day we opened it, Flo listed tracking via purchases, location, identifiers and usage, plus a long “linked to you” list. Play said no third-party sharing, with collection of location, personal info and seven other types, encryption in transit, and deletion on request.

Clue has no matching FTC order in our search. Its 14 July 2026 policy says health data is stored in the EU and names processors such as AWS and Braze. Play still said some personal and health types may be shared. Apple listed identifier tracking. EU hosting is a location fact, not a promise that no processor ever sees a field. If you switch apps, export first. Uninstalling is not deletion.

Evidence and medical-device claims

Clue support (3 March 2026) is unusually clear: the fertile-window estimate in Period Tracking mode was never tested in a research study and must not be used to prevent pregnancy. Conceive mode uses a different algorithm. Apple’s device note limits Conceive to an aid for conception. The listing still says do not use Clue as contraception.

Jennings et al. (2019) followed 718 women using the Dot app for 6,616 cycles. Abstract typical-use failure was 5.0% (95% CI 3.4–6.6%); the full text also reports 5.8% (95% CI 3.57–8.09%). Perfect use was 1.0% (95% CI 0.9–2.9%). Clue later said it acquired that algorithm. Those figures are not a 2026 Flo vs Clue bake-off. They are not a licence to skip clinic contraception.

Li et al. (2020) used historic Clue logs (378,000-plus person-cycles in the abstract) to describe cycle and symptom variation. That paper does not score Plus forecasts. We found no matching PubMed accuracy trial for 2026 Flo predictions.

NHS irregular-period pages still start with a changed pattern, periods longer than seven days, bleeding between periods, or three missed periods. An export from either app can help that visit. It cannot finish it. If training pain is the real problem, see exercise warning signs. After illness, pace return with return to exercise after illness. For how much movement guidelines actually ask for, see UK and US physical activity guidelines.

Who should skip both

Skip both if you need contraception from an app. Skip both if a nightly fertility colour will raise anxiety you cannot use. Skip both if you will not edit a wrong prediction after a late period.

This Flo vs Clue page does not rank a winner. Flo fits people who want chats and Anonymous Mode and will read the 2021 FTC file. Clue fits people who want Berlin hosting and a simpler Plus grid. If neither fits, the parent hub lists other diaries.