Wake up refreshed, not groggy.
A free, science-backed sleep calculator for working professionals. Find the best bedtime, wake-up time, power nap length and recover sleep debt — all in your browser, no signup.
We assume 15 minutes to fall asleep and align your wake/sleep to complete 90-minute cycles. The highlighted option is the recommended sweet spot for adults (5–6 cycles).
Recommended bedtimes
To wake up refreshed at 7:00 AM
Smart insights from your AI Sleep Coach
Personalised, rule-based guidance that updates with every calculation.
Advanced sleep tools
Tap a card to expand. Everything runs in your browser.
Power nap calculator
Pick 20, 30 or 90 minutes for an energising, grogginess-free nap.
Shift-worker planner
Build a darkness window around your shift to anchor circadian rhythm.
Sleep debt tracker
Estimate weekly debt from your average nightly sleep.
Productivity insights
See your peak focus, creative and admin windows for tomorrow.
Smart alarm suggestions
Get a 10-minute alarm window aligned with cycle ends.
AI Sleep Coach
Quick check-in for personalised, evidence-based suggestions.
7-day sleep planner
Auto-build a one-week schedule of bedtimes, wake-ups & naps. Export to Google Calendar (.ics) or save as PNG.
Who benefits most from the Sleep Calculator?
Whether you're chasing a promotion, surviving rotating shifts, training for a marathon, or just trying to stop hitting snooze five times — aligning your wake-up with a complete sleep cycle changes everything. Below are the people who get the biggest measurable lift from cycle-based sleep planning, backed by research from the National Sleep Foundation and circadian-rhythm studies at Harvard Medical School.
Working Professionals
9-to-5 employees gain ~22% more focus in the morning by waking at the end of a 90-minute cycle. Stop fighting brain fog before your first coffee — start meetings sharp, finish admin faster, and reclaim your evenings.
Corporate Employees & Managers
Back-to-back meetings, late emails, jet-lag from client travel — our planner aligns your bedtime with your calendar so you arrive at the 9 AM stand-up energised, not exhausted. Includes a smart-alarm window to avoid mid-cycle wake-ups.
Founders, Freelancers & Remote Workers
Flexible schedules are a double-edged sword. Lock in a consistent wake time, plan deep-focus blocks 90 minutes after waking, and use our productivity peaks tool to ship 2× more in half the hours.
Shift Workers, Nurses & Doctors
Night shifts, on-call rotations and 12-hour ER shifts wreck circadian rhythm. The shift-planner generates a sleep window + pre-shift power nap so you stay alert when it matters most — and recover properly on days off.
Students & Exam-Prep Aspirants
Memory consolidation happens in REM — the cycles you skip with all-nighters. Plan 5–6 full cycles before exams, sync revision blocks with peak-alertness windows, and retain up to 40% more on test day.
Athletes & Fitness Enthusiasts
Growth hormone peaks in deep sleep (cycles 1–3). Time your bedtime for 8 hours of complete cycles to maximise muscle recovery, reduce injury risk and shave seconds off your PB.
New Parents
Sleep in fragments? Use the nap planner to grab a 20-minute alertness boost or a 90-minute REM cycle while baby naps — proven to reduce postpartum exhaustion without the groggy hangover.
Frequent Travellers
The time-zone selector adjusts every recommendation to your destination. Pre-shift your sleep before international flights and cut jet-lag recovery from 5 days to 2.
Anyone Battling Insomnia or Burnout
Use the sleep-debt calculator to see exactly how much you owe yourself, then let the AI coach build a 7-day recovery plan with bedtime, wake-time and habit fixes that actually stick.
How 90-minute sleep cycles work
Each cycle moves you through light, deep and REM sleep. Waking at the end of a cycle feels easy. Waking mid-cycle feels groggy.
- Cycle 1–2 (0–3 hrs): Mostly deep sleep — physical recovery.
- Cycle 3–4 (3–6 hrs): Balance of deep and REM — memory & immunity.
- Cycle 5–6 (6–9 hrs): REM-heavy — creativity, focus & emotional regulation.
- Adults need 5–6 full cycles for peak next-day performance.
Hover the bars to compare cycle depth.
Bar height = average proportion of deep + REM sleep per cycle.
Sleep calculator FAQs
Quick answers about cycles, naps and sleep debt.
Sleep happens in roughly 90-minute cycles. Waking at the end of a cycle feels easier than waking mid-cycle. The calculator counts back (or forward) in 90-minute blocks and adds 15 minutes to fall asleep.
Most adults feel best with 5 to 6 full cycles per night — about 7.5 to 9 hours of sleep.
20 minutes for a quick refresh, 30 minutes for memory and alertness, or a full 90-minute cycle to include REM without grogginess.
Partially. Catching up on 1–2 hours over a weekend helps short-term alertness, but consistent nightly sleep is the only real fix.
Block 7.5 hours of darkness around your main sleep, anchor it to the same clock time daily, and use a 20-minute nap before night shifts.