Oura Ring Sleep Scores May Be as Accurate as a Coin Flip

A class-action lawsuit filed against Oura, maker of the popular smart ring, alleges its sleep-tracking feature is shockingly unreliable. According to the complaint, the ring’s AI guesses your sleep stages with only 53% accuracy—barely better than a coin toss. That’s a big deal for the millions of people who’ve spent around $500 on the device hoping to get real insights into their sleep quality.

The lawsuit argues that sleep happens in the brain, not on your finger, and that Oura lacks the medical-grade sensors needed to accurately measure brain activity during sleep. Instead, the ring uses heart rate, body temperature, and breathing data to guess when you’re in deep, light, or REM sleep. A Nature study cited in the lawsuit backs up the claim, finding the ring’s sleep staging accuracy to be "limited."

Oura isn’t backing down. The company says its technology is backed by peer-reviewed science and that sleep stages *can* be inferred from wrist or finger data. But if the lawsuit succeeds, it could force Oura—and potentially other sleep-tracking wearables—to prove their claims or change how they market their products. The outcome might also push buyers to question whether these devices are worth the hype.

For now, the lawsuit is a wake-up call for anyone relying on a smart ring or watch to diagnose sleep problems. If you’re using one of these devices to make health decisions, you might want to take its results with a grain of salt—or at least set your expectations accordingly.