Luna vs Clue: which private cycle tracker fits you in 2026?

Luna and Clue agree on the thing most cycle apps get wrong: your data should not be the product. Where they differ is what each one does on top of that.

Side by side

Short answer

Both apps are a safe choice if privacy is what worries you. Clue is EU-based in Berlin, runs no ads, and does not sell data. Luna is EU-based in Frankfurt with the same boundaries.

The real difference is the layer on top.

Clue is a clean tracker. It logs, it predicts from your averages, and it stays out of the way. Luna keeps that privacy posture and adds an interpretation layer: a cycle-aware AI that answers from your own logs, and a partner mode that shares context without exposing private data.

So the question is not "which one is more trustworthy." It is "do you want a quiet tracker, or a tracker that helps you make sense of your patterns day to day."

What Clue does well

Clue has been privacy-serious since long before it was fashionable.

It is EU-based, gender-neutral by design, and built around a science-leaning, data-visualization approach. There are no ads anywhere in the product, and the company has never relied on selling cycle data as a business model.

If you want a tracker that feels clean, credible, and free to start, Clue delivers that without compromise. Its gender-neutral design, which avoids assumptions about who uses the app, was ahead of most competitors for years.

For a lot of people, that is genuinely enough. A private, clear, well-built calendar is all they want from a cycle app.

Where Luna goes further

The clearest differences are the things Clue deliberately leaves out.

1. A cycle-aware AI, not just a calendar

When you ask "why am I more tired this week?", Luna answers from what you have actually logged, not a generic phase template. After a few weeks of tracking, the answers get specific to your patterns. Clue does not have a chat that reads your logs and responds.

2. A partner mode that does not leak

Luna lets you share useful context with a partner, where you are in your cycle, what tends to help, while keeping your notes, temperature, and intimacy logs private. It is built for support, not surveillance, and it works for couples of any gender. Clue has no partner feature.

If you want to see how that boundary should be designed: how partner sharing should work in an app.

3. Ranges instead of a fixed calendar

Luna shows predictions as ranges with a confidence level that improves as it learns your cycle. When your cycle varies, Luna says so instead of projecting one confident date. Clue predicts from your averages, which is reasonable, but with less signal about uncertainty.

For why that matters: why period predictions are ranges, not exact dates.

Privacy, compared honestly

This is where many comparisons would try to find a gap. There is not much of one.

Both apps host in the EU. Both run no ads. Neither sells your data. Both let you delete your account, though Luna makes it a one-tap action.

If EU hosting is a deciding factor for you, both pass. The deeper read on what that actually guarantees is here: EU hosting for health apps.

So privacy is not the tiebreaker between Luna and Clue. Features are.

Pricing & access

Clue can be used for free, which is a real advantage if you want private tracking at no cost. Luna is paid because it is not supported by ads, and the AI and partner features cost something to run. A tracker can monetize your data or charge a subscription, and Luna chose the subscription.

Which app is better depending on what you want

If you want a free, clean, private tracker

→ Clue

If you want private tracking plus daily interpretation

→ Luna

If you only log and check predictions

→ Clue

If you want an AI that answers from your own patterns

→ Luna

If you want to share cycle context with a partner safely

→ Luna

If you want a science-leaning calendar without extras

→ Clue

The useful takeaway

Luna and Clue are not really competitors on privacy. They are two honest answers to the same problem, with different scope.

Clue makes more sense if you want a clean, EU-hosted tracker with no ads and no extras, ideally for free.

Luna makes more sense if you want that same privacy posture and a layer of interpretation on top: a cycle-aware AI and a partner mode that keeps private data private.

If you are still weighing the bigger mainstream option too, the three-way read is here: Flo vs Luna vs Clue. And for the full privacy field: best private period tracking apps.

Related reading

• Flo vs Luna vs Clue: honest comparison
• Best private period tracking apps
• How private should a period tracker be?
• EU hosting for health apps
• How partner sharing should work in an app

If you want Clue-level privacy with daily guidance and a partner mode on top, that is what Luna is built for. 1 month free, $4.99/month after, cancel any time. EU-hosted.