Key facts
- Prices were read on UK maker pages on 2026-10-16: Withings Sleep Analyzer £129.95, Fitbit Charge 6 £139.99, Polar Loop £149.50, Amazfit Helio Ring £149.90, Garmin CIRQA £179.99. 1
- In a laboratory study of 53 adults, six devices agreed with the sleep lab on sleep versus wake 86% to 89% of the time, but only 50% to 65% of the time on sleep stages. 7
- In a study against polysomnography, devices were sensitive to sleep, with low-to-medium specificity (0.18 to 0.54) for detecting wake, and they did worse on nights of disrupted sleep. 8
- NICE says cognitive behavioural therapy for insomnia (CBTi) is the standard first treatment for people with long-term insomnia. 14
How was this comparison made, and what was not tested?
This is a dated comparison, not a ranking. Chutex has not slept with any of these devices. Each cell comes from a maker’s UK page or a published study and carries a source number, and where a page did not state a fact the cell says so. Prices and features were read on 2026-10-16 and will change.
Maker pages are commercial sources. They tell you what a company says its device measures and what it charges. The accuracy section later on uses published studies, which test particular models on small groups, so a finding for one device does not carry over to another.
Wrist, ring, band or under-mattress: which type?
The type of device changes what is comfortable and what is measured. The table sets out each type, what the maker says it measures, and the known limit from the studies read.
| Type | Example read | What the maker says it measures | Known limit from a study | Source |
|---|---|---|---|---|
| Under the mattress | Withings Sleep Analyzer | Breathing rate, heartbeat and movement through a sensor under the mattress, and snoring through a sound sensor. It is not worn. | No independent study of this device was read. The test against polysomnography is Withings’ own claim. | 1 |
| Screenless band | Polar Loop, Garmin CIRQA, Elio | Sleep stages, a morning score, heart rate variability and skin temperature, depending on the device. | The six wearables tested agreed with a sleep lab on stages 50% to 65% of the time in one study. | 23167 |
| Band with a screen | Fitbit Charge 6 | Automatic sleep tracking with light, deep and REM sleep and a Sleep Score. | Seven consumer devices, one of them an older Fitbit model, had specificity of 0.18 to 0.54 against polysomnography. | 48 |
| Ring | Amazfit Helio Ring, Oura | Sleep stages, naps and sleep breathing quality (Amazfit), stages and heart measures (Oura). | Stage accuracy of 53.18% for Oura in a clinical study, with large individual errors. | 5610 |
Maker descriptions are marked by the source number of the maker’s page. The limits come from study abstracts and apply to the models tested.
A band or ring keeps working if you move between beds, but it must be worn. An under-mattress sensor suits someone who does not want anything on the body, but it also records the movement of whoever else is in the bed.
What do the main sleep trackers offer and cost?
| Device | Form | Price | Plan | Sleep features the maker lists |
|---|---|---|---|---|
| Withings Sleep Analyzer | Under-mattress sensor 1 | £129.95 1 | Optional Withings+ at £89.50 a year, with a free month 1 | Breathing, heartbeat, movement and snoring. The page also lists sleep apnoea episodes with severity classification and does not state a UK regulatory status 1 |
| Polar Loop | Screenless band 2 | £149.50 2 | None, as Polar describes it 2 | Light, deep and REM sleep and interruptions, a morning score, no light or screen at night, 29 g 2 |
| Garmin CIRQA | Screenless band 3 | £179.99 3 | None required 3 | Sleep score, stages, heart rate variability and skin temperature 3 |
| Fitbit Charge 6 | Band with screen 4 | £139.99 4 | Google Health Premium: three months included, then £7.99 a month 4 | Automatic sleep tracking, light, deep and REM stages and a Sleep Score. Up to 7 days of battery 4 |
| Amazfit Helio Ring | Ring 5 | £149.90 5 | None announced 5 | Light, deep and REM stages, naps and sleep breathing quality 5 |
| Oura | Ring 6 | Ring: not stated on the page read. Membership £5.99 a month or £69.99 a year 6 | Required for the daily insights 6 | Not taken from the page read |
| Elio (Chutex) | Screenless band 16 | £264 as shown on its UK page, no VAT shown 16 | None, one-time payment 16 | Duration, stages, sleep latency, respiratory rate and skin temperature, with a sleep score. Wellness indicators, not a diagnosis 16 |
| WHOOP | Screenless band | No British price read. The France page shows annual prices in euros, not used here | Not stated on the page read | Not taken from a UK page |
Read on 2026-10-16 from each maker’s page. The pages do not all say whether VAT is included, and the Elio page shows none. The WHOOP row has no British price: read from France on 2026-10-16, the British address redirected to a French-language page, whose euro prices were not used, and a reader in the UK may see a different page.
The cheapest purchase price in the table is the Withings Sleep Analyzer at £129.95, and the lowest for a worn device is the Fitbit Charge 6 at £139.99. Neither is a recommendation: the Withings sensor is a different kind of tool, and the Fitbit plan is optional but renews at a price after three months.
How accurate are sleep stages?
This is the part to read before you buy. Consumer devices are reasonably good at one thing, which is telling whether you are asleep or awake, and much weaker at sorting sleep into light, deep and REM.
| Study | Who and what | Finding | Source |
|---|---|---|---|
| Sensors 2022 | 53 adults, one night in a lab, six wearables | Sleep versus wake agreement of 86% to 89%. Sleep stage agreement of 50% to 65%. The authors say all six devices need improvement on specific stages. | 7 |
| Chinoy 2021, Sleep | 34 adults, three nights, seven consumer devices against polysomnography | High sensitivity (at least 0.93) but specificity of 0.18 to 0.54. Stage assessments were inconsistent. Devices tended to do worse on nights of poorer or disrupted sleep. | 8 |
| Khan 2025, meta-analysis | Six studies, 388 participants, Oura Ring | No statistically significant difference from polysomnography or actigraphy for total sleep time, efficiency and stages. | 9 |
| Herberger 2025, Sci Rep | Sleep-clinic patients, ring trackers | The average agreement hides large individual errors, which rules out use in clinical sleep medicine. | 10 |
| Dial 2025, Physiol Rep | Overnight heart rate variability against ECG | Oura devices had the highest accuracy, WHOOP 4.0 was described as moderate, and the Garmin Fenix and Polar Grit X Pro were weaker. | 17 |
All five are abstracts. They test specific models (for example Oura Gen 3 and Gen 4, Fenix 5S, Fitbit Alta HR) and mostly small groups of healthy adults.
Two practical points follow. First, a night when you slept badly is exactly when a tracker is most likely to be wrong, which is awkward if you bought one to understand bad nights.8 Second, the stage split is the least reliable output. If you want to understand what the stages are, read sleep stages and deep sleep first.
How can you compare two devices over seven nights?
If you are torn between two devices, you can wear both for a week and compare. This is a method for you to follow. Chutex has not run it.
- Wear both every night. Put one on each wrist, or one device on the wrist and a second under the mattress. Use the same pair for all seven nights.
- Note the time you fell asleep. Write the sleep-onset time each device reports, and the time you believe you fell asleep.
- Subtract. Work out device A minus device B for each night, in minutes.
- Take the middle value. Sort the seven differences and pick the fourth. This is the median, and one odd night will not drag it far.
- Judge how you feel. Add a plain line each morning on how rested you felt. The device is meant to help with that, not replace it.
Here is an invented example to show the arithmetic. Suppose the seven differences, in minutes, are 4, minus 2, 9, 5, 0, 12 and minus 3. Sorted, they read minus 3, minus 2, 0, 4, 5, 9, 12, so the median is 4Â minutes. The mean is 25 divided by 7, about 3.6Â minutes. The two are close, and 4Â minutes is small next to the natural night-to-night variation. If the median had been 30Â minutes, the devices would disagree about what counts as falling asleep. These numbers are made up and are not typical values.
What does a sleep tracker cost over three years?
| Device | Purchase price | Plan, if kept for 36Â months | Three-year total | Source |
|---|---|---|---|---|
| Withings Sleep Analyzer | £129.95 | Withings+ yearly: 3 x 89.50 = £268.50 | £398.45 with the plan, £129.95 without | 1 |
| Polar Loop | £149.50 | None | £149.50 | 2 |
| Garmin CIRQA | £179.99 | None required. Garmin Connect+ is optional at £6.99 a month | £179.99, or £431.63 with Connect+ monthly (179.99 + 36 x 6.99) | 3 |
| Fitbit Charge 6 | £139.99 | Premium after three included months: 33 x 7.99 = £263.67 | £139.99, or £403.66 with Premium kept | 4 |
| Amazfit Helio Ring | £149.90 | None announced | £149.90 | 5 |
| Oura | Ring price not stated on the page read | 36 x 5.99 = £215.64 monthly, or 3 x 69.99 = £209.97 yearly | Not calculable without the ring price | 6 |
| Elio (Chutex) | £264 as shown, no VAT shown | None | £264 as shown | 16 |
Plans on the Withings and Garmin devices are optional. The Fitbit offer is listed until 26/05/27 and can be cancelled. The figures are ceilings for someone who keeps the plan, not predictions. The Elio price is shown without VAT.
When does tracking make sleep worse?
Some people become anxious about their scores. The term for the pattern is orthosomnia, a preoccupation with getting perfect sleep data. A 2024 cross-sectional study of 523 adults found that 176 regularly used a sleep-tracking device, and it estimated the prevalence of orthosomnia, by an algorithm the authors built, at 3.0% to 14.0% depending on how strict the threshold was.11 The authors note that a cross-sectional design cannot show cause, so this does not prove that trackers cause the problem.
If a score is making you tense, stop looking at it for a fortnight. The NHS Every Mind Matters advice is to keep regular bed and wake times and to avoid phones, tablets and computers for an hour before bed.15 Neither requires a device. For more, see how to improve sleep quality.
When should you see a GP instead of buying a tracker?
A tracker does not diagnose or treat a sleep problem. The NHS says to see a GP if you have had trouble sleeping for months or it is affecting daily life, and that a GP can suggest cognitive behavioural therapy (CBT).12 NICE describes CBTi as the standard first treatment for long-term insomnia, after sleep hygiene advice.14
For possible sleep apnoea, the NHS says a GP who suspects it may refer you to a specialist sleep clinic for tests, and that it can be serious if it is not diagnosed and treated.13 Chutex’s Elio page says that clinical sleep testing remains the reference for suspected sleep apnoea or severe insomnia.16 A device on your wrist or under your mattress does not replace that. For the hours of sleep most adults need, see how much sleep you need.
Other devices are compared in best smart rings, best fitness trackers and Oura vs WHOOP.
Frequently asked questions
What is the most accurate sleep tracker?
No study read for this page makes one device the winner. In a 2022 laboratory study, agreement on sleep stages ran from 50% to 65% across six devices, and results depend on the model and the night.
Do I need a sleep tracker?
No. A tracker can show trends, but it is not needed to improve sleep. The NHS Every Mind Matters advice is to keep regular bed and wake times and to avoid screens for an hour before bed.
Is a ring or a watch better for sleep?
It is mostly a matter of comfort. A ring is lighter and needs sizing, and a band has an adjustable strap. Studies show neither gives a reliable split into light, deep and REM sleep.
Are sleep stages on a tracker reliable?
Not very. In one laboratory study, agreement with polysomnography on stages was 50% to 65%, and a second study found devices did worse on nights of disrupted sleep.
Can a sleep tracker diagnose sleep apnoea?
No. The NHS says a GP who suspects sleep apnoea may refer you to a specialist sleep clinic for tests, and the authors of a clinical ring study said individual errors ruled out use in clinical sleep medicine.
Do sleep trackers need a subscription?
It depends. On prices read on 2026-10-16, Polar says the Loop has none, the Garmin CIRQA does not require one, and Oura charges £5.99 a month or £69.99 a year. The Withings Sleep Analyzer has an optional plan at £89.50 a year.
Sources
- Withings UK, Sleep Analyzer (product page), Withings. Retrieved 16 October 2026
- Polar UK, POLAR Loop, Polar. Retrieved 16 October 2026
- Garmin UK, CIRQA Smart Band, Garmin. Retrieved 16 October 2026
- Google Store UK, Fitbit Charge 6, Google Store. Retrieved 16 October 2026
- Amazfit UK, Helio Ring, Amazfit. Retrieved 16 October 2026
- Oura, Membership (footnote on prices by country), Oura. Retrieved 16 October 2026
- A validation of six wearable devices for estimating sleep, heart rate and heart rate variability in healthy adults (Sensors, 2022), abstract, PubMed. Retrieved 16 October 2026
- Chinoy et al., Performance of seven consumer sleep-tracking devices compared with polysomnography (Sleep, 2021), abstract, PubMed. Retrieved 16 October 2026
- Khan et al., The Oura Ring versus sleep studies, systematic review and meta-analysis (OTO Open, 2025), abstract, PubMed. Retrieved 16 October 2026
- Herberger et al., Performance of wearable finger ring trackers for diagnostic sleep measurement in the clinical context (Sci Rep, 2025), abstract, PubMed. Retrieved 16 October 2026
- Jahrami et al., Prevalence of orthosomnia in a general population sample (Brain Sci, 2024), abstract, PubMed. Retrieved 16 October 2026
- NHS, Insomnia (last reviewed 19 March 2024), NHS. Retrieved 16 October 2026
- NHS, Sleep apnoea (last reviewed 11 May 2026), NHS. Retrieved 16 October 2026
- NICE, Daridorexant for treating long-term insomnia (TA922), recommendations (published 18 October 2023), NICE. Retrieved 16 October 2026
- NHS Every Mind Matters, How to fall asleep faster and sleep better, NHS. Retrieved 16 October 2026
- Chutex, Elio health band (UK product page), Chutex. Retrieved 16 October 2026
- Dial et al., Validation of nocturnal resting heart rate and heart rate variability in consumer wearables (Physiol Rep, 2025), abstract, PubMed. Retrieved 16 October 2026