Log bedtime + wake time and instantly see your sleep duration, 7‑day average, sleep debt, and a Consistency Score designed for screenshots and sharing. Everything runs locally in your browser — no account, no sign‑up.
Add each night as a single entry. If your sleep crosses midnight (most people do), this tracker handles it automatically. You can track naps too — just flip the “Entry type”.
localStorage. Clearing browser data will remove them.
This tracker turns your bedtime and wake time into a single thing: duration. From there, it builds the three numbers that matter most for real life: a rolling average, a sleep debt estimate, and a Consistency Score that rewards “steady” nights over “random” nights.
For each entry, the calculator converts your times into minutes after midnight. If your wake time is “earlier” than your bedtime (for example, bedtime 11:30 PM and wake time 7:00 AM), the tracker assumes your sleep crossed midnight and adds 24 hours to the wake time.
Duration (minutes) = (wake minutes + dayOffset) − bedtime minutes
Where dayOffset is 0 if wake time is after bedtime, and 1440 minutes if wake time is earlier (meaning it’s the next day). Then it converts minutes to hours:
Duration (hours) = Duration (minutes) ÷ 60
The tracker separates “night sleep” from “naps” so the averages reflect your main sleep. (You’ll still see naps in your history table and totals, but they don’t inflate your nightly average by default.)
For a window like 7 days, the calculator takes the most recent 7 days’ worth of night entries and computes:
Average = (sum of nightly durations) ÷ (number of nights logged)
If you logged fewer nights, it uses what you have — but your average becomes more reliable as your streak grows.
Sleep debt is not a perfect scientific concept, but it’s a very useful “reality check.” The tracker asks: if your goal is G hours per night, how far are you above or below that goal across the last 7 nights?
Debt (hours) = (G × N) − (sum of durations over N nights)
If the number is positive, you’re below your goal (debt). If negative, you’re above your goal (surplus). The tracker shows it as a friendly number like “+2h 30m debt” or “−1h 00m surplus”.
People often chase “more sleep” but ignore “more consistent sleep.” Your body loves rhythm. So this tool turns your last 7 nights into a Consistency Score.
Step 1: compute the standard deviation (how spread out your nightly durations are). If your nights are very similar, standard deviation is small. If your nights swing wildly, it’s big.
Step 2: convert deviation into a score:
Consistency Score = clamp(100 − (StdDevHours ÷ 2.5 × 100), 0, 100)
This maps about 0 hours deviation to ~100 score, and about 2.5 hours deviation to ~0. Then we clamp it between 0 and 100.
Note: This is a simple tracker, not a medical device. But simple trackers win because you’ll actually use them.
Imagine you hit around 8 hours some nights… but you also have 5-hour nights. Your weekly average might look fine, but your Consistency Score will reveal the hidden problem: large swings.
Your average is roughly 7.3h, but your schedule is “spiky,” so your Consistency Score may land in the 50–70 range. Most people feel better fast by reducing the spikes (even without increasing the average).
You choose a goal of 7.5h and keep your nights within ±20–30 minutes:
Your Consistency Score will usually be very high (often 90+). Even if your average is “only” 7.5h, many people report feeling more awake because their body can predict the pattern.
Bedtime 11:45 PM, wake time 6:30 AM:
That’s 6 hours 45 minutes — and you can see exactly where the number comes from.
If you log a nap (say 1:20 PM → 1:55 PM), it will appear in your history and can raise your total sleep for the day, but by default it won’t inflate your nightly averages or your Consistency Score (which is meant to reflect your main rhythm).
Most trackers overwhelm you with charts. This one is intentionally lightweight: it gives you a repeatable loop you can actually stick with.
If your schedule is chaotic (travel, parenting, shift work), you can still benefit: focus on a realistic window (like “I aim for 7–8 hours”) and track the trend rather than chasing a perfect week.
This tool estimates time in bed based on the times you enter. Actual sleep can be lower if you take a long time to fall asleep or wake up during the night. Still, time in bed is a strong “good enough” proxy for most people who want simple tracking.
This tracker is “one-entry-per-sleep” to keep it fast. If you want to capture multiple segments, you can add a note (e.g., “awake 2–3am”) or log two entries (a nap entry plus a night entry). The tool stays flexible — it won’t yell at you.
Duration is the simplest thing you can measure accurately with one tap. Bedtime consistency matters too, but many people can’t control bedtime (work, kids, travel). If you want to stabilize bedtime, use the Chronotype Finder and Smart Alarm Window.
You’ll get a duration instantly from a single entry. For averages and consistency, results become meaningful after about 3–7 nights. The score is intentionally “sticky” to reduce overreacting to one weird night.
Most adults do well around 7–9 hours, but your personal goal depends on your lifestyle and how you feel. A useful approach: pick a goal, track for 2 weeks, then adjust based on energy and mood.
Yes — tracking duration and consistency makes it obvious when jet lag is stealing sleep. Pair this with the Jet Lag Recovery Calculator.
Naps count for total rest, but they don’t represent your main nighttime rhythm. That’s why the tool lists naps but keeps them out of the nightly consistency score by default. If you’re a nap-heavy person, use the Nap Length Calculator too.
On your device, in your browser, using localStorage. No servers, no login, no account. If you clear browser storage, the entries disappear — which is why some people screenshot their results for “proof.” 😄
That’s a surplus — you slept above your goal over the last week. It doesn’t mean you can “bank” unlimited sleep, but it’s a useful sign your recent recovery is strong.
This simple version focuses on speed + virality. If you want exports, you can copy the table or screenshot it. (If you want, you can add a CSV export button later using the same saved data.)
MaximCalculator provides simple, user-friendly tools. Always treat results as informational, and double-check any important health decisions with a professional.