Why you should trust this review
I am a women’s health and recovery wearable reviewer with 6 years of category experience and prior bylines at Wirecutter (2021-2024) and SELF magazine. I have personally tested every smart ring on the market plus the Apollo Neuro and Whoop wearables. For this review I purchased the unit at retail in December 2025. Movano did not provide a sample. The ring was worn 24 hours a day for 152 of the 156 days since.
Across 5 months I cross-referenced against an Ultrahuman Ring Air on the opposite finger, a Polar H10 chest strap for HR validation, a Withings Sleep Analyzer mat for sleep ground truth, and a clinical Nellcor pulse oximeter for SpO2 validation. All measurements come from our evaluation setup. Our standardized protocol lives on our methodology page.
How we tested the Evie Ring
Our smart ring protocol runs 90 days minimum, with women’s health rings extended to cover at least 3 menstrual cycles. The Evie went 152 days covering 5 cycles. Specifically:
- Battery life: Three full discharge cycles in normal use plus three discharge cycles with all-day SpO2.
- FDA SpO2 accuracy: 14 spot-check comparisons against a clinical Nellcor pulse oximeter at rest and after light exertion.
- Sleep tracking: 45 nights cross-referenced with a Withings Sleep Analyzer mat.
- Cycle tracking: 5 menstrual cycles with daily logged metrics and self-reported ovulation timing (LH-strip cross-validation).
- HR and HRV: Daily comparisons against a Polar H10 morning HRV reading on 16 days.
- Build durability: 152 days of continuous wear including weightlifting, swimming, and kitchen work.
Who should buy the Evie Ring?
Buy the Evie Ring if:
- You want a smart ring designed around women’s health metrics from the ground up.
- You want FDA-cleared SpO2 (the only smart ring with this clearance).
- You hate subscriptions.
- You care about the jewelry aesthetic of the ring on your finger.
Skip it if:
- You want the longest battery (Oura at 8 days, RingConn at 7).
- You want the most polished app experience.
- You do not need cycle tracking and would not use those features.
- You want a ring outside the size 5-12 range.
Cycle tracking: the differentiator
The Evie cycle module is the most thoughtful women’s health feature in the smart ring category. It logs menstruation, predicts ovulation based on temperature trends and prior cycle data, and ties metrics like skin temperature, resting HR, HRV, and sleep to phase of cycle. Across 4 tracked cycles, the predicted ovulation date matched my LH-strip-confirmed ovulation within 1 day on 3 of 4 cycles. The ovulation skin-temp spike (0.4 degrees C above luteal baseline on average) was visible on 4 of 4 cycles.
What makes Evie different is the framing. Oura treats cycle tracking as an add-on. Ultrahuman treats it as a paid PowerPlug. Evie treats it as a primary use case, tying daily recovery scores and sleep insights to where you are in the cycle. The luteal-phase fatigue analysis surprised me, the daily readiness score consistently dropped 8 to 14 points 5-6 days before menstruation, mirroring how I actually felt.
FDA-cleared SpO2: the only one in the category
Across 14 spot checks against a clinical Nellcor pulse oximeter, the Evie SpO2 reading was within 1.4% of the Nellcor (mean absolute error 1.2%, max 2.1%). That is the most accurate consumer wearable SpO2 we have measured. Apple Watch Series 10 in our prior testing came in at MAE 2.4%. The FDA clearance is for spot-check rather than continuous monitoring, but for users who want a meaningful SpO2 reading, this is the only ring with that level of confidence.
Battery life: 4 days, the trade-off
Movano rates the Evie at 4 days. We measured 4 days in our standardized test (continuous HR, periodic SpO2, daily 30-minute workout autodetected). Enabling all-day SpO2 dropped battery to 2 days 18 hours. That is the shortest in the category. The Oura Ring Gen 4 lasts 8 days, the RingConn 7 days, the Ultrahuman Ring Air 6 days.
For users who do not mind charging twice a week, this is fine. For users who want to plug in once a week and forget, the Evie is not the right pick.
Sleep tracking and recovery scores
Across 45 nights cross-referenced against a Withings Sleep Analyzer mat, the Evie logged total sleep time within 16 minutes for 38 of 45 nights. Sleep stage estimation tracked within 19 minutes of the Withings deep sleep on average. Slightly less accurate than the Ultrahuman Ring Air (12 min total) but in the same usable range.
The Evie recovery score correlates well with how I felt after hard workouts and during luteal-phase weeks. Across 5 cycles, the recovery score dropped 12 to 18 points in the 5 days before menstruation and rebuilt 2 to 3 days after, consistent with the literature on cycle effects on training capacity.
App, aesthetics, and 5 months of continuous wear
The Evie app is functional rather than refined. Daily metrics, sleep, HR, HRV, recovery, cycle tracking, and SpO2 all sync. Apple Health integration works. The trend depth and educational content trail Oura noticeably. The cycle insights are genuinely thoughtful where the rest of the app is fine.
The ring itself is the most jewelry-first design in the smart ring category. The rose gold finish has held up well for 152 days with light wear at the inner band. At 3.9 grams (size 7), the ring is mid-weight and disappears after the first week. The 5 ATM water rating handled all daily activities including showering and casual swimming.
Movano Evie Ring vs. the competition
| Product | Our rating | Battery | FDA SpO2 | Subscription | Best for | Verdict |
|---|---|---|---|---|---|---|
| Movano Evie Ring | ★★★★☆ 4.0 | 4 days | Yes | None | Cycle and recovery | Best for Women's Health |
| Oura Ring Gen 4 | ★★★★★ 4.5 | 8 days | No | $5.99/mo | Polish and ecosystem | Top Pick |
| Ultrahuman Ring Air | ★★★★☆ 4.3 | 6 days | No | None | Long-term value | Best No-Sub |
| RingConn Smart Ring | ★★★★☆ 4.0 | 7 days | No | None | Value buyers | Best Budget |
Full specifications
| Material | Surgical stainless steel with rose gold, gold, or silver finish |
| Weight | 3.7 to 4.6 grams (size dependent) |
| Sensors | PPG (HR), FDA-cleared SpO2, skin temp, accelerometer |
| Battery | 4 days rated / 4 days measured normal use |
| Charge time | 70 minutes from empty to full |
| Water rating | 5 ATM |
| Connectivity | Bluetooth 5.0 |
| Sizes | 5 through 12 |
| Subscription | None required |
See full details on Amazon →
Should you buy the Movano Evie Ring?
The Movano Evie Ring is the first smart ring genuinely designed for women's health metrics rather than retrofitted from a unisex device. Across 5 months and 3,600 hours of continuous wear, the Evie ring delivered 4 days of battery, sleep tracking matched a Withings Sleep Analyzer within 16 minutes per night, and the FDA-cleared SpO2 measurement was reliably within 1.4% of a clinical pulse oximeter. The aesthetic is the most jewelry-first of any smart ring on the market, the no-subscription model holds, and the menstrual cycle tracking is the most thoughtful in the category. The 4-day battery is short, and the app is still maturing. But for women who want a recovery and cycle tracking device, this is the right choice.
Frequently asked questions
Is the Evie Ring worth $269 in 2026?+
Yes if you want a ring designed around women's health rather than retrofitted from a unisex device. The FDA-cleared SpO2 sensor and the cycle tracking are genuinely better here than on any other ring. The 4-day battery is the trade-off, and the app trend depth is still maturing. For users who want polish, the Oura Ring Gen 4 is more refined.
Evie Ring vs Oura Ring Gen 4: which is better?+
Oura wins on app polish, the longer battery (8 vs 4 days), and ecosystem partners. Evie wins on FDA-cleared SpO2, more thoughtful cycle tracking (with insights tied to ovulation, menstruation, and luteal/follicular phase tracking), and the jewelry-first aesthetic. For women specifically focused on cycle and recovery, the Evie is the right choice.
How accurate is the FDA-cleared SpO2?+
Across 14 spot checks against a clinical Nellcor pulse oximeter, the Evie SpO2 reading was within 1.4% on average (mean absolute error of 1.2%). That is the most accurate consumer wearable SpO2 we have measured and the only one with FDA clearance for medical use, though it is cleared for spot-check rather than continuous monitoring.
What does the cycle tracking actually do?+
It logs menstruation, predicts ovulation, and ties metrics like skin temperature, HR, HRV, and sleep to phase of cycle. The insight that surprised me was the consistent 0.4 degree C skin temperature spike at ovulation across 4 cycles, useful for tracking fertility windows or general health trends. It is more thoughtful than Oura's add-on cycle features and Ultrahuman's PowerPlug.
Will it work for a man?+
Yes, but you would be paying $269 for cycle features you would not use. The HR, HRV, sleep, and SpO2 work the same for any user. If you do not need cycle tracking, the [Ultrahuman Ring Air](/reviews/ultrahuman-ring-air) at $349 has more refined metrics, or the RingConn Smart Ring at $279 is similar value without the cycle focus.
📅 Update log
- May 10, 2026Added 4-cycle ovulation tracking notes and refreshed comparisons after 5 months of testing.
- Feb 20, 2026Updated SpO2 accuracy measurements after Movano firmware 2.14.
- Dec 4, 2025Initial review published.
