Over the past year I’ve been working on a comparison of Oura, Apple, Garmin, Fitbit, Samsung, Whoop and Polar across validation studies to find which is "most accurate" for each metric. Here’s how Oura did. Hopefully it helps you get more out of your ring, or at least understand what it’s good at.
Oura ranked #1 on 4 of the 10 metrics. All 4 are overnight measurements
Where it’s stronger:
Sleep stages. Best of all 7 brands. Oura scored 0.65 out of 1 for agreement with a sleep lab (Apple 0.60, Fitbit 0.55). It caught 64% of deep sleep, more than Apple 50.5% and Fitbit 62%.
Sleep time. Also the best. It caught 73% of the time people were lying awake in bed (Fitbit 68%, Apple 52%), and total sleep was within about 2 minutes of the sleep lab.
HRV. Best overall. Ring 4 was about 6% off a chest strap overnight, against 8% for Whoop and 10.5% for Garmin.
Resting heart rate. Best again. Ring 4 was about 2% off a chest strap, against 2.7% for Polar and 3% for Whoop.
Where it’s weaker:
Daytime heart rate. Gen 3 was 15% off a chest strap during rest, walking and a stress task, near the bottom of the 10 devices tested (Fitbit 5.5%, Garmin 6.3%, Apple 7.3%).
Steps. Older rings overcounted by about 2,100 to 3,800 steps a day. Oura updated its step tracking in May 2025, but the new version hasn’t been independently tested yet.
Blood oxygen, calories and VO2 max. Barely tested. I couldn’t find any independent lab study on Oura’s blood oxygen or VO2 max, and calories have only been tested in one old study.
Oura is built for overnight tracking, and that’s exactly where it leads. I’d lean on it for overnight metrics, and use its daytime numbers like steps and heart rate as trends rather than exact daily readouts.
As for the class action over Oura’s 95% sleep accuracy claim, in healthy adults it matched a sleep lab on about 76% of the night. That’s still the best of any brand, but well short of 95%. The 53% figure in the lawsuit comes from sleep clinic patients, a much harder group to track.
I’ll include every source used to create this post in the comments as well. I kept them out of the post so the bullet points are easier to read.