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Healthcare · head to head

Clue vs Sleep Cycle

Clue logo

Clue

Healthcare

Period and cycle tracking app owned by German company Biowink, positioned around science based tracking and a published stance against sharing data with law enforcement

From
Free
Rated
-
Full reviewWebsite
Sleep Cycle logo

Sleep Cycle

Fitness

Phone based sleep tracking app that uses the microphone or accelerometer to detect sleep phases and wake you in a light sleep window

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Clue clues stated policy on not sharing data with law enforcement without a valid legal process is the companys own published position and legal interpretation, not an independent guarantee, and it can still be compelled to comply with a legally binding request under EU or other applicable law.; Sleep Cycle sleep stage detection is inferred from sound and motion rather than measured with dedicated physiological sensors, so accuracy is lower than a ring or watch based tracker like Oura.
  • They diverge on capability: Clue covers Cycle and symptom tracking, Sleep Cycle covers Sound and motion sleep analysis.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Clue and Sleep Cycle actually diverge.

Attributes where Clue and Sleep Cycle differ
AttributeClueSleep Cycle
Pricing modelFree with a Plus subscriptionFree with a Premium subscription
CategoryHealthcareFitness

Identical on both: starting price (Free), free tier (Yes), platforms (iOS, Android), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Clue

  • Cycle and symptom tracking
  • Cycle insights and patterns
  • Research partnerships
  • EU-based data hosting
  • Fertility and conception mode
  • Perimenopause and other life stage tracking

Only in Sleep Cycle

  • Sound and motion sleep analysis
  • Smart alarm
  • Sleep quality trends
  • Snore and sleep talk recording
  • Sleep aid sounds and stories
  • Apple Health and wearable integration

What people use each for

The jobs each tool is most often brought in to do.

Clue

  • Someone specifically weighing data jurisdiction and legal exposure when choosing a period tracking app, given Clues EU basis and published stance on law enforcement requestsnot Sleep Cycle
  • A user who wants cycle tracking positioned around scientific research partnerships rather than lifestyle or community contentnot Sleep Cycle
  • A buyer comparing Clue directly against Flo on current published privacy policy language before choosing which app to trustnot Sleep Cycle
  • Someone tracking perimenopause or other non-standard cycle stages that some period apps do not support wellnot Sleep Cycle

Sleep Cycle

  • Someone who wants sleep tracking without buying a ring or watch, using a phone they already ownnot Clue
  • A person who struggles with grogginess from alarms and wants to be woken during a light sleep window insteadnot Clue
  • Someone who wants to check whether they snore or talk in their sleep, which requires the Premium subscriptionnot Clue
  • A buyer comparing upfront cost against Oura or a smartwatch before deciding whether hardware-free tracking is good enoughnot Clue

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Clue

  • Clues stated policy on not sharing data with law enforcement without a valid legal process is the companys own published position and legal interpretation, not an independent guarantee, and it can still be compelled to comply with a legally binding request under EU or other applicable law.
  • Deeper cycle insights and predictions, the features most likely to justify tracking in the first place, are gated behind the Clue Plus subscription rather than fully free.
  • Being a smaller company than some competitors, Clue has less capital and legal resource to contest large-scale legal requests than a larger, better-funded rival might, despite its stated intent to do so.
  • Research partnerships using anonymised user data, while opt-in, still mean user-derived data can be used in ways beyond direct app functionality, and users should check current consent settings.
  • Cycle predictions rely on self-reported data and general population models, so accuracy for irregular cycles or specific medical conditions remains limited regardless of which app is used.

Sleep Cycle

  • Sleep stage detection is inferred from sound and motion rather than measured with dedicated physiological sensors, so accuracy is lower than a ring or watch based tracker like Oura.
  • The app needs to run overnight with the microphone active or the phone on the mattress, which raises its own privacy consideration for anyone uncomfortable with a phone microphone recording an entire room overnight.
  • Most of the features that make the sleep data actionable, detailed trends and snore analysis, are behind the Premium subscription rather than included free.
  • Battery drain overnight from continuous microphone or motion sensing is a real practical issue for anyone who also wants to use the phone as a normal alarm without charging it.
  • Detection can be disrupted by a shared bed, a partners movement or snoring, or ambient household noise, all of which reduce accuracy for the primary user.

Pricing, plan by plan

Clue

Free
  • Clue Plus$9.99/month
    • Free tier covers core cycle tracking, logging and basic predictions
    • Clue Plus adds deeper cycle insights, extended predictions and personalised content
    • Annual Plus plans typically offered at a lower effective monthly rate

Sleep Cycle

Free
  • Sleep Cycle Premium$39.99/year
    • Basic sleep tracking and the smart alarm are free, no hardware required
    • Premium unlocks detailed trends, snore recording playback and most sleep sounds
    • Annual Premium commonly around $39.99, with a higher effective rate if billed monthly

Which should you pick?

Choose Clue if

  • You need cycle and symptom tracking.
  • You want to start without paying.
  • You work on iOS, Android.
  • You also want cycle insights and patterns.
Clue review

Choose Sleep Cycle if

  • You need sound and motion sleep analysis.
  • You want to start without paying.
  • You work on iOS, Android.
  • You also want smart alarm.
Sleep Cycle review

Questions people ask

Is Clue or Sleep Cycle better?
Neither clearly leads. Clue starts at Free and Sleep Cycle at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Clue or Sleep Cycle?
Clue starts at Free and Sleep Cycle at Free.
Does Clue or Sleep Cycle run on more platforms?
Both run on iOS, Android, so platform support will not decide this one for you.
Can I use Clue for free?
Both have a free tier, so you can try either at no cost before committing.
What is Clue best used for?
Clue is most often used for someone specifically weighing data jurisdiction and legal exposure when choosing a period tracking app, given clues eu basis and published stance on law enforcement requests, a user who wants cycle tracking positioned around scientific research partnerships rather than lifestyle or community content, a buyer comparing clue directly against flo on current published privacy policy language before choosing which app to trust, someone tracking perimenopause or other non-standard cycle stages that some period apps do not support well. Of those, someone specifically weighing data jurisdiction and legal exposure when choosing a period tracking app, given clues eu basis and published stance on law enforcement requests and a user who wants cycle tracking positioned around scientific research partnerships rather than lifestyle or community content are not what Sleep Cycle is typically brought in for.
What can Clue do that Sleep Cycle cannot?
Clue covers Cycle and symptom tracking, Cycle insights and patterns, Research partnerships, EU-based data hosting. Sleep Cycle covers Sound and motion sleep analysis, Smart alarm, Sleep quality trends, Snore and sleep talk recording.

Answered from the vendors’ own pages

Clue: Does Clue share data with law enforcement?

Clue publishes a policy stating it does not share health data with law enforcement or public authorities without a legally binding request and states it will challenge requests it considers improper. This is the companys stated position; verify the current policy directly for specifics.

Sleep Cycle: Do I need to buy any hardware for Sleep Cycle?

No. It uses your phones microphone or accelerometer, placed on the nightstand or mattress, with no separate device to buy.

Clue: Why does Clue emphasise being an EU company?

Clue operates under EU GDPR data protection rules and states this legal basis makes it harder for authorities outside the EU, including US authorities, to compel data disclosure than for a company based in the US.

Sleep Cycle: Is Sleep Cycle free?

Basic tracking and the smart alarm are free. Detailed trends, snore recording and most sleep sounds require Sleep Cycle Premium.

Clue: Is Clue free?

Core cycle tracking, logging and basic predictions are free. Deeper insights and extended predictions require Clue Plus.

Sleep Cycle: How accurate is phone based sleep tracking compared with a ring or watch?

Less accurate, since it infers sleep stages from sound and motion rather than measuring heart rate or temperature directly, which dedicated wearables like Oura do.

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