Sleep

Sleep cycle calculator: enter your wake-up time and get the best bedtimes based on 90-minute sleep cycles plus time to fall asleep. Free and instant.

Add up your last week of sleep and see your sleep debt in hours, what it does to you, and a realistic recovery plan. Free, instant, private.

Caffeine half-life calculator: enter your coffee and timing to see how many mg are still in your system at bedtime, with fast/slow metabolizer settings.

Clean, generated white noise with a sleep timer and volume fade. No loops, no ads in the audio, works offline — free in your browser.

Deep, low-frequency brown noise generated live in your browser — the warm rumble many people find steadier than white noise. Sleep timer included.

Balanced pink noise generated in your browser — softer highs than white noise, studied for sleep quality. Free, with a fade-out sleep timer.

Slow, rolling ocean waves generated live — no loop seams, no video ads. The sound of ballast doing its work. Free with a sleep timer.

Soft, steady rain generated in your browser — endless, seamless, and free, with a sleep timer and volume fade for drifting off.