Hespera: Sleep Time Calculator

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About this app

Hespera is a sleep calculator and sleep tracker that turns the day you
actually lived into a clear plan for tonight. No wearable, no sensors —
just tell Hespera what happened today.

SLEEP CALCULATOR AND BEDTIME PLANNER
Set the time you need to wake up and the sleep calculator works backwards
through your sleep cycles to find your bedtime. Waking between cycles
instead of in the middle of one is why you can sleep eight hours and still
feel wrecked. Hespera gives you a bedtime target, a wake-up window and a
wind-down reminder, then adjusts the whole sleep schedule around the day
you actually had — a long nap, a hard workout, a stressful afternoon.

CAFFEINE TRACKER AND CUTOFF TIMER
Log coffee, tea and energy drinks. Hespera shows how much caffeine is
likely still in your system at bedtime and finds the caffeine cutoff that
fits your routine. Most people underestimate this by hours, and it is
usually the single biggest reason they cannot fall asleep fast.

SLEEP DEBT AND RECOVERY
Short nights add up. The sleep debt tracker shows what you owe, how one
late night reaches into more than one morning, and how your recovery is
going across the week. No guilt, no streaks to break — just the number.

SLEEP QUALITY, SCORED AND EXPLAINED
Every night gets a sleep quality score, and every score comes with the
reasons behind it: caffeine, stress, late food, screen time, alcohol,
naps, exercise. You see what moved the number, not just the number.

NAP PLANNER AND WAKE WINDOWS
Plan naps that help instead of wrecking your night. Hespera picks nap
length and timing from your current sleep debt and your bedtime target,
and keeps your wake window intact.

ENERGY THROUGH THE DAY
See when you are likely to feel alert and when the dip is coming. Hespera
reads your sleep history to forecast tiredness, so you can schedule the
hard work for the hours that will actually cooperate.

SLEEP DIARY AND HISTORY
Hespera keeps a clean sleep log. Browse your sleep journal night by night,
open any night to inspect it, correct a bedtime or wake-up time you got
wrong, and skip nights you do not want counted. Bad data makes bad
insights, so Hespera lets you keep the record honest.

REAL PATTERNS, NOT GENERIC TIPS
Hespera compares caffeine, stress, exercise, naps, alcohol and screen time
against your own nights and shows which habits keep appearing alongside
better or worse sleep. Insights arrive only when there is enough data to
mean something — one unusual night proves nothing.

BUILT FOR REAL SCHEDULES
Irregular hours, shift work, early alarms, travel. Hespera does not assume
you sleep eleven to seven. It calculates around the schedule you have.

WHY HESPERA
- Sleep calculator, sleep tracker and caffeine timer in one app
- No wearable needed — works on your phone alone
- Sleep cycle and REM estimates from your own logged nights
- Bedtime and wake-up reminders you can actually keep
- Sleep hygiene guidance built into the plan, not bolted on
- Clean, quiet design that does not nag

You do not need a perfect routine or another list of generic sleep tips.
Tell Hespera what happened today and use it to make tonight better.

Hespera is not a medical device and is not intended to diagnose, treat,
cure or prevent any medical condition or sleep disorder. If you have
serious or persistent sleep problems, consult a qualified healthcare
professional.
Know when to sleep tonight. Bedtime calculator, sleep cycles, naps, caffeine.
Updated on
Sep 14, 2026
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Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • No data shared with third parties
    Learn more about how developers declare sharing
  • No data collected
    Learn more about how developers declare collection

What’s new

— Morning reminders now wait for a plan worth closing.
— Alcohol is easier to log: choose a level, not a count.
— Scores are judged against your own clean night.
— About You can be edited later without rewriting past nights.
— Sleep need now has an exact ruler, and Today follows it.
— Charts open the night behind the number, keeping architecture, debt and energy in one story.