Smart Nap Calculator
Time your daytime nap to boost alertness without waking up groggy in slow-wave deep sleep.
Not sure which nap length to pick? Quick guide
A 20–26 min power nap keeps you in light sleep so you wake sharp without grogginess. Avoid 45-min alarms, which often cut into deep N3 sleep. When heavily sleep-deprived, a 90-min full cycle completes every stage.
Power Nap
Best AlertnessStays in light N1/N2 sleep to restore focus and motor performance without grogginess.
NASA Pilot Nap
Research BenchmarkModeled after NASA fatigue studies showing major gains in vigilance and reaction speed.
Inertia Risk Zone
Avoid Alarm HereWaking around 40–60 minutes often pulls you straight out of deep N3 sleep, causing heavy fog.
Full Cycle Recovery Nap
Deep RecoveryCompletes light, deep, and REM stages to pay back acute sleep deficit.
Contoured 3D Blackout Eye Masks
Block ambient office or midday light during 20-minute power naps without pressing on eyelashes.
Explore Blackout Mask SpecsFrequently Asked Questions
How long is an ideal power nap without grogginess?
A 20 to 26-minute power nap keeps the brain in light N1 and N2 sleep before slow-wave deep sleep sets in, boosting alertness without triggering sleep inertia.
When should I take a full 90-minute recovery nap?
If you are severely sleep deprived, a 90-minute full cycle nap lets you complete light, deep, and REM stages and wake near a natural transitional boundary.
What is the latest safe time of day for a nap?
Most sleep medicine specialists recommend finishing daytime naps before 3:00 PM to 3:30 PM so homeostatic sleep pressure (adenosine) can rebuild by bedtime.
Optimize the rest of your 24-hour sleep routine
Pair your cycle window with caffeine timing, power naps, or weekly sleep debt tracking.