Sleep Calculators
Bedroom Temperature Optimization Calculator
Compare your current bedroom temperature against the sleep-research-recommended optimal range for better sleep quality.
Bedtime Calculator
Enter a target wake-up time to see bedtime options aligned to complete 90-minute sleep cycles, spanning 3 to 6 cycles of overnight rest.
Blue Light Screen Cutoff Calculator
Calculate the recommended time to stop screen use before bed based on your target bedtime and a screen cutoff buffer.
Caffeine Half-Life Sleep Calculator
Calculate how much caffeine is still active in your system based on time elapsed and caffeine half-life, relevant to sleep quality.
Caffeine Nap Timing Calculator
Learn the correct timing for a 'caffeine nap' - drinking coffee immediately before a short nap so caffeine kicks in right as you wake.
Circadian Rhythm Calculator
Estimate your natural chronotype from unforced bedtime and wake time, using the sleep midpoint method behind the MCTQ research questionnaire.
Daylight Saving Time Adjustment Calculator
Calculate a gradual bedtime shift schedule to ease into a Daylight Saving Time transition with less circadian disruption.
Jet Lag Recovery Calculator
Estimate jet lag recovery time in days based on time zones crossed and travel direction, since eastward and westward adjustment rates differ.
Melatonin Timing Calculator
Calculate a general reference time to align melatonin timing with a target bedtime, based on common lead-time guidance.
Nap Length Calculator
Compare power nap, recovery nap, and full-cycle nap lengths to match your goal, from a 20-minute alertness boost to a full 90-minute cycle.
Optimal Nap Window Calculator
Calculate the ideal nap window based on your wake-up time, aligned with the natural post-lunch circadian dip in alertness.
REM Sleep Calculator
Estimate REM sleep duration in hours and minutes from total sleep time, using the typical 20-25% REM share seen in healthy adult sleepers.
Shift Work Sleep Schedule Calculator
Calculate a recommended sleep window for shift workers based on shift end time and total sleep need.
Sleep Consistency Score Calculator
Calculate a sleep consistency score based on night-to-night bedtime and wake time variance.
Sleep Cycle Calculator
Find bedtimes or wake-up times aligned to complete 90-minute sleep cycles, based on 3 to 6 full cycles plus 15 minutes to fall asleep first.
Sleep Debt Calculator
Track accumulated sleep debt or surplus across several nights by comparing your recommended sleep hours against actual hours slept each night.
Sleep Efficiency Calculator
Calculate sleep efficiency as the percentage of time in bed actually spent asleep, rated against the commonly used 85% healthy benchmark.
Sleep Latency Calculator
Calculate sleep latency, the time it takes to fall asleep after lights-off, and see how it compares to normal ranges.
Sleep Need Calculator
Look up recommended nightly sleep duration by age group, from newborn through older adult, using established age-banded sleep guidelines.
Wake Up Time Calculator
Enter a bedtime to see wake-up times aligned to the end of a 90-minute sleep cycle, for 3, 4, 5, or 6 complete sleep cycles overnight.
Sleep Comes in 90-Minute Blocks
Sleep is not a uniform block of rest — it cycles through stages roughly every 90 minutes, and waking up mid-cycle is a big part of why some 8-hour nights still feel groggy while a slightly shorter night can feel fine. These ten calculators work with that cycle structure.
Why Sleep Duration Recommendations Come in Odd Numbers
This is why the Bedtime Calculator and Wake Up Time Calculator work backward or forward in 90-minute increments rather than just targeting a flat 8 hours — landing between cycles, even at 6.5 or 7 hours total, often beats waking up mid-cycle at a nominally "fuller" 8 hours.
Popular Sleep Calculators
- Sleep Debt Calculator — totals accumulated sleep deficit across recent nights against your sleep need.
- Jet Lag Recovery Calculator — estimates recovery time after crossing time zones based on direction and zones crossed.
- Circadian Rhythm Calculator — estimates your natural sleep-wake timing based on chronotype indicators.
Related: Health Calculators, Mental Health Calculators.