Compare
Polar Loop with Keely, or Oura.
Both read your night and score how ready you are each morning. An Oura Ring 5 costs $399 to $499, and a membership, $5.99 a month or $69.99 a year, unlocks everything beyond its three daily scores. A Polar Loop is $199.99 once, and Keely is free. Oura is a ring and measures blood oxygen; Keely adds a training Load with a daily target and live stress, and publishes every formula.
Updated
At a glance
| Polar Loop with Keely | Oura Ring 5 | |
|---|---|---|
| Price (US) | $199.99 for the Loop, once. Keely is free | $399 to $499 (Ring 4 is still sold from $349) |
| Membership | None | $5.99 a month or $69.99 a year. Without it: the Readiness, Sleep and Activity scores only |
| Worn as | A band on the wrist | A ring |
| Morning score | Recovery, 0–100 %: HRV, resting heart rate, sleep, breathing rate and skin temperature | Readiness, 0–100: resting heart rate, HRV balance, temperature, sleep and activity |
| Effort | Load: points per minute by heart-rate zone, no ceiling, with a daily target and Balance | Activity score, 0–100 |
| Stress | Live, 0–100, scored only while you’re still | Daytime Stress in four zones (stressed, engaged, relaxed, restored), with a membership |
| Sleep | Stages from the Loop, need (goal, debt and a hard day), consistency and a lights-out time | Sleep score, 0–100, with stages; detailed sleep with a membership |
| Formulas | Every input, weight and constant is published | Contributors are described; Oura calls its algorithms proprietary |
| Sensors | Optical heart rate, accelerometer, skin temperature | Adds blood oxygen |
| Battery, by the maker | Up to 8 days (Polar’s figure, with Polar Flow) | 6 to 9 days (Ring 4: 5 to 8) |
| Water | WR30: swimming, not diving | Water-resistant to 100 m |
| Your data | Raw heart data stays on your iPhone; your account backs up daily summaries | Stored in your Oura account; the API needs a membership |
Facts about Oura come from Oura’s own pages, checked September 28, 2026. This page compares cost, scores and data; it doesn’t test sensor accuracy.
Cost over two years
At today’s US prices, with the yearly membership and no discounts:
| First year | Two years | |
|---|---|---|
| Polar Loop with Keely | $199.99 | $199.99 |
| Oura Ring 5 with membership | $468.99 to $568.99 | $538.98 to $638.98 |
| Oura Ring 4 with membership | $418.99 | $488.98 |
Oura includes one month of membership with a new ring, so its first year can come in slightly lower.
Where Oura does more
- A ring. Some people find a ring easier to wear every night than a band.
- Blood oxygen, plus features Keely doesn’t have: Cardiovascular Age, Cardio Capacity (a VO₂ max estimate), Resilience, and Health Radar in some countries.
- Water resistance to 100 m, against the Loop’s 30.
- Your data, out. An API with a membership. Keely doesn’t export yet.
Where Keely is different
- No membership. You buy the Loop once, and Keely is free. Oura’s scores beyond Readiness, Sleep and Activity need a membership.
- Training Load with a target. Keely counts every minute by its heart-rate zone and sets a range for the day from your Recovery and your last four weeks. See Load.
- Stress as a number, live. From 0 to 100 while Keely is open, and never scored while you move. See Stress.
- Every formula is public. On the methodology page.
- Your raw heart data stays on your iPhone.
Frequently asked questions
Is the Polar Loop with Keely an Oura alternative without a membership?
Yes. You buy the Loop once, and Keely gives you a morning Recovery score, a Load target, live stress and sleep against your need, free. Oura’s membership is $5.99 a month or $69.99 a year.
Is Keely’s Recovery like Oura’s Readiness?
Both score last night against your own normal from HRV, resting heart rate, sleep and temperature, from 0 to 100. They’re different calculations, so the numbers won’t match. Keely’s is on its Recovery page.
Can I use an Oura Ring with Keely?
No. Keely works with the Polar Loop.
Sources
- Oura Ring 5: Oura’s store and Discover Oura Ring 5. Ring 4: Oura’s store.
- Membership: Oura Membership (updated September 8, 2026).
- Scores: Readiness, Sleep, Activity and Daytime Stress.
- Polar Loop price: Polar’s US store. Specifications: Polar Loop user manual.
All checked September 28, 2026. Prices and features change, so check Oura’s before you buy. Oura is a trademark of Oura Health Oy; Keely isn’t affiliated with or endorsed by Oura or Polar.
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