Surprisingly decent smart ring for under $80 — perfect for curious beginners
Visit COLMI →The COLMI R02 is one of the cheapest smart rings you can buy in 2026, with a retail price hovering around $79 — that's less than a quarter of what you'd pay for an Oura Ring Gen 4. COLMI is a Chinese wearable brand known for budget smartwatches and fitness trackers, and the R02 is their entry into the fast-growing smart ring category. We wore the R02 for two weeks to see if a ring this cheap could actually deliver useful data, and the results were... mixed, honestly. For $79, you get a surprising amount on paper: heart rate monitoring, basic sleep tracking, step counting, calorie estimation, and even SpO2 blood oxygen tracking. The stainless steel build feels decent in hand, if a bit heavy, and the ring is water-resistant enough for showering and swimming. Battery life is impressive for the price — we got about 5-6 days per charge with regular use. The problems start when you look at accuracy. Sleep tracking is rough at best, often missing naps or misclassifying deep sleep as light sleep. Heart rate readings are consistently 5-10 BPM higher than what we got from reference devices. And the companion app feels like an afterthought — clunky, full of ads, and lacking any meaningful insights or integration with other health platforms. Still, if you're dead set on trying a smart ring but can't or won't spend $200+, the COLMI R02 is a low-risk way to dip your toes in the water. Just don't expect medical-grade accuracy or a premium experience.
At around $79, the COLMI R02 is one of the most affordable smart rings on the market. It costs less than a single year of Oura's subscription, making it a low-risk way to try smart ring technology without committing hundreds of dollars.
Despite the budget price, the R02 delivers respectable battery endurance. In our testing, we consistently got 5-6 days between charges with heart rate and sleep tracking enabled. The magnetic USB charger tops it up in about 2 hours.
Rated IP68 for dust and water resistance, the R02 can be submerged up to 50 meters. Wear it in the shower, the pool, or even while swimming laps — just don't expect the heart rate sensor to work accurately underwater.
Tracks heart rate, sleep stages (light/deep/REM), steps, calories, and even blood oxygen (SpO2). It's not the most accurate, but it gives you a general sense of your activity and sleep patterns for a very low investment.
| Material | Stainless steel with zirconia ceramic coating |
|---|---|
| Thickness | 3.2mm |
| Weight | 8-12g (size-dependent) |
| Width | 8.0mm |
| Sensors | PPG optical sensor, 3-axis accelerometer |
| Tracked Metrics | Heart rate, basic sleep stages, steps, calories, SpO2 |
| Battery Life | 5-6 days |
| Charging | Magnetic USB charger, ~2 hours to full |
| Water Resistance | IP68 (up to 50m) |
| Size Range | US sizes 6-12 |
| Subscription | None required |
| Price | $79 |
| Feature | COLMI R02 | Go2Sleep Ring | Oura Ring Gen 4 |
|---|---|---|---|
| Starting Price | $79 | $149 | $349 |
| Subscription | None | None | $5.99/mo |
| Battery Life | 5-6 days | 7-10 days | 7 days |
| Material | Stainless steel | Plastic | Titanium |
| Weight | 8-12g | 3g | 4-6g |
| Sleep Accuracy | Mediocre | Good | Best-in-class |
| Temperature Tracking | No | No | Yes |
| Best For | Absolute budget beginners | Budget sleep tracking | Premium accuracy |
It depends on your expectations. If you want accurate health data and a polished experience, no — spend the extra money on Go2Sleep or RingConn instead. But if you're curious about smart rings and only want to spend $80 to try the form factor, the R02 is fine. It'll give you a general sense of how smart rings work without a major financial commitment. Just don't expect medical-grade accuracy.
It's rough. In our side-by-side testing with Oura Ring Gen 4, the COLMI R02 got total sleep time within about 30 minutes on most nights, but sleep stage classification was hit-or-miss. It frequently misclassified deep sleep periods and sometimes completely missed naps. Think of it as a general indicator, not precise data.
No, the COLMI R02 doesn't integrate with Apple Health, Google Fit, Strava, or any other major health platform. All your data stays within the COLMI app, which is one of the biggest downsides compared to more established brands. If you want your health data in one place, look elsewhere.
The stainless steel shell is reasonably durable — we wore it daily for two weeks without any major scratches or damage. The bigger concern is long-term software support. Budget brands like COLMI don't have the best track record for app updates and long-term support, so the ring might feel outdated sooner than premium options.
The COLMI R02 is the definition of "you get what you pay for." At $79, it's by far the cheapest way to try a smart ring, and it delivers a basic level of sleep and activity tracking that might be enough for casual users who just want a general sense of their patterns. But the accuracy is mediocre, the app is clunky and ad-supported, and there are zero third-party integrations. If budget is your absolute top priority and you just want to dip your toes into smart rings, it's a low-risk purchase. If you can stretch your budget to $149, the Go2Sleep Ring offers significantly better accuracy and a better overall experience. And if you want the real deal, save up for Oura or RingConn.
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