Flo vs Clue: which period tracker is more private in 2026?

Flo and Clue are the two names most people compare first. They are both large, well-known, and capable, but they sit on opposite sides of one question: how a period tracker should treat your data.

Side by side

The short version

If your priority is privacy, Clue is the more private of the two. It is hosted in the EU (Berlin), runs no ads, and does not sell your data as a business model. Its gender-neutral, science-leaning design has been consistent for years.

If your priority is a polished, mainstream, feature-rich experience, Flo is the bigger, more familiar product, with a large user base and broad language support.

The catch is what made many people start comparing the two in the first place: Flo's data history.

What changed for Flo

In August 2025, a US jury reached a verdict in a class action against Flo and Meta, confirming that Flo had shared sensitive health data, including period and pregnancy tracking, with Facebook between 2016 and 2019. Flo had earlier settled an FTC case in 2021 and has updated its data practices since.

This matters in a Flo vs Clue comparison for one reason: it is the clearest example of why hosting and business model are not abstract concerns. An ad-supported, US-hosted app and an ad-free, EU-hosted one are different by design, not just by reputation.

For the wider context: do period apps sell your data?

Where Flo wins

Flo is the more complete mainstream product.

It has a polished interface, a very large user base, broad language support, and a feature set that covers most things people expect from a consumer health app. If you want the most familiar, feature-rich experience and privacy is a background concern for you, Flo is a reasonable pick.

Where Clue wins

Clue wins on privacy posture and restraint.

It is EU-hosted, ad-free, and has never built its business on selling cycle data. The design is clean and gender-neutral, and it has solid scientific backing. If you want a credible, low-cost tracker that takes privacy seriously, Clue is the stronger of the two.

What Clue does not have: an AI assistant that answers from your logs, or a partner mode. It is a clean tracker, not a guided one.

Where Luna fits

If reading "Flo vs Clue" is really you asking "which one respects my data," there is a third option worth knowing about.

Luna is EU-hosted (Frankfurt), runs no ads, and never sells data, the same privacy posture as Clue. On top of that, it adds what Clue leaves out: a cycle-aware AI that answers from your own logs, honest predictions shown as ranges, and a privacy-filtered partner mode that never exposes your notes, temperature, or intimacy logs.

So the three-way picture is simple. Flo is mainstream convenience. Clue is privacy without extras. Luna is privacy with guidance. The full head-to-heads are here: Flo vs Luna vs Clue and Luna vs Clue.

Which should you choose

If you want a mainstream, feature-rich app

→ Flo

If you want EU privacy at low or no cost

→ Clue

If you want EU privacy plus guidance and a partner mode

→ Luna

If the Meta verdict is what brought you here

→ Clue or Luna, depending on whether you want extras

The useful takeaway

Flo vs Clue is really mainstream convenience versus EU privacy. Clue is the more private of the two; Flo is the more feature-rich.

If privacy is what is driving your search, Clue is a strong answer, and Luna is worth a look if you also want a cycle-aware AI and a partner mode on top of that same EU-hosted, ad-free posture.

Related reading

• Flo vs Luna vs Clue: honest comparison
• Luna vs Clue: which private tracker fits you
• Best private period tracking apps
• Do period apps sell your data?
• How private should a period tracker be?

If "Flo vs Clue" is really about who respects your data, Luna gives you EU hosting and no ads, plus guidance and a partner mode. 1 month free, $4.99/month after, cancel any time.