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Polar Loop with Keely, or WHOOP.
Both give you a Recovery score from 0 to 100 % each morning, a measure of the day’s effort, and sleep against your need. WHOOP is a membership, from $199 a year with the band included. A Polar Loop is $199.99 once, and Keely is free. WHOOP measures more, including blood oxygen; Keely publishes every formula and keeps your raw heart data on your iPhone.
Updated
At a glance
| Polar Loop with Keely | WHOOP 5.0 and MG | |
|---|---|---|
| Price (US) | $199.99 for the Loop, once. Keely is free | A membership with the band included: One $199, Peak $239 or Life $359 a year |
| Subscription | None | Required. New members choose 12 or 24 months |
| Morning score | Recovery, 0–100 %: Primed, Balanced or Restore | Recovery, 0–100 %: green, yellow or red |
| What it weighs | HRV, resting heart rate, sleep, breathing rate and skin temperature | HRV, resting heart rate, sleep performance, respiratory rate, blood oxygen and skin temperature |
| Effort | Load: points per minute by heart-rate zone, linear with no ceiling, and a target range each morning | Strain: 0–21, logarithmic by design, from heart-rate zones and muscular load |
| Stress | Live, 0–100, scored only while you’re still | Stress Monitor, 0–3, on Peak and Life |
| Sleep | Stages from the Loop, need (goal, debt and a hard day), consistency and a lights-out time | Sleep performance, need (baseline, strain, debt and naps), consistency |
| Formulas | Every input, weight and constant is published | Inputs are described; WHOOP says the weights aren’t published |
| Sensors | Optical heart rate, accelerometer, skin temperature | Adds blood oxygen; WHOOP MG adds an ECG |
| Battery, by the maker | Up to 8 days (Polar’s figure, with Polar Flow) | 14+ days |
| Alarm | None: the Loop can’t vibrate | Haptic alarm |
| Your data | Raw heart data stays on your iPhone; your account backs up daily summaries | Stored in your WHOOP account, with a CSV export and a developer API |
Facts about WHOOP come from WHOOP’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 no discounts:
| First year | Two years | |
|---|---|---|
| Polar Loop with Keely | $199.99 | $199.99 |
| WHOOP One | $199 | $398 |
| WHOOP Peak | $239 | $478 |
| WHOOP Life | $359 | $718 |
Where WHOOP does more
- More sensing. Blood oxygen on every tier. WHOOP MG, on the Life tier, adds an FDA-cleared ECG (Heart Screener) and Blood Pressure Insights.
- A haptic alarm. The Loop has no vibration motor, so it can’t wake you silently.
- Battery. 14+ days, and on Peak and Life a PowerPack that charges the band on your wrist.
- More features. Healthspan (WHOOP Age), AI coaching, a strength trainer and hormonal insights.
- Your data, out. A CSV export and a developer API. Keely doesn’t export yet.
- Where you wear it. WHOOP’s sensor also fits its own garments and a bicep band.
Where Keely is different
- No subscription. You buy the Loop once, and Keely is free.
- Every formula is public. Recovery’s weights, Load’s points and every constant are on the methodology page, so any number can be checked.
- Load has no ceiling. WHOOP describes Strain as logarithmic: two workouts of 10 don’t add up to 20. Keely’s Load is linear, so twice the work is twice the Load, and each morning brings a target range set by your Recovery.
- Stress from 0 to 100, day and night. Live from the Loop while Keely is open, and never scored while you move. See Stress.
- Your raw heart data stays on your iPhone. Only daily summaries are backed up to your account.
Frequently asked questions
Is the Polar Loop with Keely a WHOOP alternative without a subscription?
Yes. You buy the Loop once, and Keely turns it into a morning Recovery score, a Load target, live stress and sleep against your need, free. WHOOP includes its band in a membership that starts at $199 a year.
Is Keely’s Recovery the same as WHOOP’s?
Both run from 0 to 100 % and both lean on HRV and resting heart rate, but they’re different calculations, so the numbers won’t match. Keely’s weights and formula are on its Recovery page.
Is Load the same as Strain?
No. Strain runs from 0 to 21 on a logarithmic scale, so each point is harder to earn than the last. Load counts every minute by its heart-rate zone with no ceiling: an hour in Zone 2 is about 120, and three hours about 360.
Can I use my WHOOP band with Keely?
No. Keely works with the Polar Loop.
Can I bring my WHOOP history to Keely?
Not yet. Keely starts fresh: it learns your normal over your first nights, and your first Recovery arrives after 3.
Sources
- WHOOP membership and prices: whoop.com/us/en/membership, and Membership Pricing (May 28, 2026).
- WHOOP 5.0 and MG: WHOOP’s launch announcement, May 8, 2025.
- Strain’s scale, and that its formula isn’t published: How does WHOOP Strain work?
- Recovery’s inputs: WHOOP 101.
- Stress Monitor: Get to know the Stress Monitor.
- Data export: How to export your data.
- Polar Loop price: Polar’s US store. Specifications: Polar Loop user manual.
All checked September 28, 2026. Prices and features change, so check WHOOP’s before you buy. WHOOP is a trademark of WHOOP, Inc.; Keely isn’t affiliated with or endorsed by WHOOP or Polar.
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