Phone-Only Sleep
Track Sleep and Energy Without a Watch
A ring or a strap is another device to charge, wear and replace. If what you want is enough signal to plan your day around, the phone already on your nightstand can supply it.
Can you track sleep without a smartwatch?
Short answer
Yes, with a phone. MaxDex fuses three signals — gaps in screen interaction, operating-system sleep classification events, and accelerometer stillness — then scores the resulting night for efficiency, disturbance and awake minutes.
Three detectors rather than one, because each fails differently: interaction gaps break during a long film, classification events are unavailable on some devices, and stillness misreads a phone left on a desk. The engine takes the best-supported candidate.
The full algorithm is published at how phone-only sleep detection works, including the parts where it performs badly.
How does it compare with dedicated wearables like an Oura ring or Whoop?
Short answer
Wearables measure biometric signals directly like heart rate and HRV. MaxDex infers sleep duration and timing from phone stillness and activity patterns, designed specifically for daily planning without buying or charging extra hardware.
Consumer wrist devices typically focus on physiological telemetry. MaxDex focuses on practical scheduling: providing actionable duration, consistency, and sleep-debt metrics for your daily plan directly from your phone.
What a phone offers is convenience: it is already beside you every night without extra subscriptions or hardware to charge.
Sources
- de Zambotti, Cellini, Goldstone, Colrain & Baker (2019). Wearable Sleep Technology in Clinical and Research Settings. — Medicine & Science in Sports & Exercise
Related
What do I get if it is not sleep stages?
Short answer
Duration, efficiency, disturbance, estimated awake minutes, a rolling seven-day sleep debt, and a bedtime consistency index — plus how all of that flows into your capacity for the day ahead.
Consistency is not a vanity metric here. Irregular sleep-wake patterns have been associated with worse performance and delayed circadian timing independently of total sleep duration, which is why it feeds the score directly.
- Rolling 7-day sleep debt against your learned personal sleep need
- Bedtime consistency, which affects recovery independently of hours
- A sleep score that penalises debt and rewards regularity
- An energy curve that shapes what the planner suggests
Does it work if I sleep during the day?
Short answer
Yes. Time of day is explicitly not a gate on what counts as sleep, and the chronotype estimate is clamped to ±12 hours so a night-shift worker resolves to a valid phase rather than an error.
Most consumer sleep tracking quietly assumes sleep happens at night and behaves oddly for anyone whose schedule does not. Typical timing is used here as a weak tie-breaker between candidate segments, never as a filter that rejects them.
Frequently asked questions
Can I track my sleep without a smartwatch or ring?
Is phone sleep tracking accurate?
Where do I put my phone at night?
Will it drain my battery overnight?
3 more questions
What happens if I forget my phone or it dies?
Does it detect naps?
Is this a good Oura or Whoop alternative?
Last reviewed August 28, 2026 by the MaxDex Services team. How we research and review this.