May 7, 2025
What Is Sleep Efficiency and What It Reveals About Your Sleep Quality
What is Sleep Efficiency?
Sleep efficiency is the percentage of time you actually spend asleep compared to the total time you spend in bed. If you want to know how to calculate your sleep efficiency, here’s the formula:
Sleep Efficiency = (Total Sleep Time ÷ Time in Bed) × 100
As the formula shows, you can calculate your sleep efficiency by dividing the total time asleep by the total time in bed, then multiplying the result by 100. The time in bed is the period between when you intend to fall asleep and when you get out of bed.
This includes the time spent lying in bed trying to fall asleep, but does not include time spent reading, talking to your partner, or using your phone before deciding to sleep.
So, if you went to bed at 11:00 PM and got up at 7:00 AM, that would be eight hours in bed. Now let’s say you were actually asleep for six of those eight hours, then your sleep efficiency was 75%. On paper, that’s easy to calculate. But in practice, the most reliable way to track your sleep efficiency over time is by using a wearable health tracker like a smartwatch, a ring, or whatever device you already use.
How Wearables Track Sleep Efficiency
Most popular wearables (WHOOP, Oura, Garmin, Fitbit, and Apple Watch) estimate your sleep efficiency score by collecting data such as resting heart rate, heart rate variability (HRV), respiratory patterns, movement, and sleep stage transitions—all of which also factor into your overall sleep score.
These devices are capable of detecting signs of fragmented sleep, which is usually the reason why you might feel tired, even after eight hours of “sleep”. However, some wearables still tend to overestimate this by missing micro-awakenings or periods of light sleep, so it’s important not to rely on the data blindly.
As you get used to your wearable and it adjusts to your patterns, pay attention to how you feel each morning and compare it to what the data shows. After several nights of tracking, you’ll start to see whether your sleep efficiency score is consistently landing in a healthy range or falling below it.
What Is a Good Sleep Efficiency Score?
Sleep researchers and most wearables define a good sleep efficiency score as anything above 85 percent. This means your sleep was stable, uninterrupted, and long enough to support full recovery.
Here’s how the typical ranges break down:
- 85% or higher is considered efficient and restorative sleep
- 75–84% may suggest restlessness or trouble falling asleep
- Below 75% usually means your sleep is getting disrupted too often
If your sleep efficiency score drops below 85 percent, your body may not be staying asleep long enough to complete the full recovery cycle. That includes deep sleep and REM, when tissue repair, hormone regulation, and memory consolidation take place.
A single bad score isn’t a reason to worry, but if you score low for several nights in a row, it may be a sign that your body isn’t getting the restoration it needs.
How To Improve Sleep Efficiency Score
There’s a common belief that to sleep better, you just need to sleep longer. But that isn’t always true. You can stay in bed for eight to ten hours and still wake up tired if your body doesn’t reach deep sleep or REM, or if you keep waking up without realizing it.
Improving sleep efficiency means helping your body stay asleep once it gets there. That depends on what you do before bed, how your environment supports rest, and how your system responds when sleep becomes unstable.
Here’s what you can try:
1. Keep a regular sleep and wake time, even on weekends
Your circadian rhythm controls when your body feels ready for sleep and when it expects to wake. When your sleep time shifts from one day to the next, your body needs more time to fall asleep and is more likely to wake up during the night. A consistent schedule helps reduce sleep onset latency and supports deeper, uninterrupted sleep.
2. Make your room darker, quieter, and slightly cooler
Light, sound, and temperature all send signals that can interrupt sleep stages. Even if you don’t wake up fully, noise or a rise in room temperature can pull you out of deep sleep and reduce sleep efficiency. Try blackout curtains, remove LED standby lights, and use earplugs or a white noise machine. Most people sleep best when the room is around 18°C (65°F).
3. Avoid heavy meals, alcohol, and screens before bed
Eating late keeps your system active when it should be slowing down. Alcohol might make you feel drowsy at first, but it usually leads to lighter sleep and more awakenings. Bright screens interfere with melatonin production and delay the natural transition into sleep. Try keeping your evenings quieter, lighter, and less visually stimulating.
4. Slow your system down before getting into bed
Sleep doesn’t begin the moment you lie down. Your body needs to shift into a lower arousal state. A warm shower, yoga exercise, or even five minutes of deep breathing can reduce your heart rate and support the parasympathetic nervous system.
5. Get more natural light and stay active during the day
Morning sunlight resets your circadian rhythm and supports melatonin release later that night. Just ten to fifteen minutes outside shortly after waking can improve your ability to fall asleep and reduce nighttime awakenings. Movement during the day builds sleep pressure, which increases the likelihood of reaching deep sleep once you fall asleep.
6. Try aromatherapy for proven sleep benefits
Aromatherapy can support sleep, especially when you use calming oils like lavender, Roman chamomile, or sandalwood. But if the scent runs for hours or stays the same every night, your brain stops responding. This is called olfactory habituation, and research shows it can start within minutes.
To avoid this, use scent briefly and in response to what your body needs according to your data.
This is what we call personalized aromatherapy for sleep.
In the next section, we show you how easy this is with Kimba.
How Kimba Can Help You Improve Your Sleep Efficiency
Kimba is the first smart diffuser that uses real-time scent therapy to support your limbic system—the part of the brain that regulates sleep, mood, and recovery.
You can connect Kimba to wearable devices you possibly already own, like Oura, Fitbit, Apple Watch, Garmin, WHOOP, and any tracker synced through Apple Health. While your wearable tracks your sleep patterns, Kimba monitors those same signals and looks for signs that your recovery may be interrupted.
Kimba responds when your heart rate stays elevated, your breathing becomes less regular, or your body shifts out of deeper sleep stages earlier than expected.
The moment your sleep needs support, Kimba delivers a short pulse of scent that is adapted to you, both in timing and quantity. The blends we use are proprietary and clinically tested, developed to work with the parts of the brain that regulate sleep and recovery.
You do not need to set timers, create new routines, or manage schedules. Kimba works automatically using the data you already trust and adapts to your body’s needs while you sleep.
If you’re already tracking your sleep efficiency and want to improve both your numbers and how you actually feel after sleep, Kimba might be just what you are looking for.
