Sleep Score: Your Sleep in One Number

The first thing you see when opening Mellows is your sleep score — a 0–100 composite that distills complex sleep data into a single, easy-to-read result.

What Determines the Score

The sleep score isn't a mapping of one metric; it's a weighted combination of multiple dimensions:

Sleep duration — Whether you got the amount of sleep your body needs. This is measured against your personal baseline, not a generic "8 hours" standard.

Sleep architecture — Whether deep sleep and REM proportions are healthy. Insufficient deep sleep impairs physical recovery; insufficient REM affects cognition and mood.

Sleep continuity — Whether you slept soundly through the night. Frequent awakenings interrupt sleep cycles and reduce recovery efficiency.

Physiological recovery — Whether heart rate, HRV, and other metrics indicate effective recovery. Low heart rate paired with high HRV is a hallmark of good restoration.

These dimensions are dynamically weighted based on data completeness and how mature your personal baseline is.

What the Score Means

• 85-100: Optimal — strong performance across dimensions; body is well-recovered
• 75-84: Good — overall solid, perhaps one dimension slightly off
• 60-74: Fair — some room for improvement
• 45-59: Poor — multiple dimensions underperforming; worth investigating causes
• Below 45: Very Poor — sleep quality significantly low; prioritize improvement

How Your Baseline Shapes the Score

This is the key difference between Mellows scoring and other apps. Once your personal baseline is established, your own standards are factored in:

For example: if your baseline deep sleep ratio is 18% and you record 20% one night, that's a good result for you. But for someone whose baseline is 25%, that same 20% would be below normal. Same data, different baselines, different scores.

The more mature your baseline (more days of use), the higher the personal weighting — and the closer the score reflects your true situation.

How to Interpret the Score

Watch trends, not single nights. A one-off 65 doesn't mean your sleep is broken — maybe you were exhausted or the room was noisy. But if you hover around 65 for a full week, it's worth digging into why.

The score is a starting point, not an endpoint. It tells you "how tonight went overall," but understanding the specifics requires looking at each dimension's detailed data.

Don't stress about the number. Research shows that obsessing over sleep data can actually cause "orthosomnia" — sleeping poorly because you're worried about sleeping poorly. Treat the score as a reference, not an exam grade.