Countdown & Duration Calculator
Count down to any date, measure time gaps between events, convert durations between formats and calculate ideal bedtimes based on 90-minute sleep cycles.
Results
How many days until Christmas? How long is the gap between two meetings? How many total seconds is a 1h 30m video? What time should I go to bed to wake up refreshed at 7 AM? These tools handle everyday time calculations that come up in event planning, scheduling, video editing, fitness tracking and sleep optimization.
Frequently asked questions
Enter the target date in the Days Until Date calculator. It shows the exact count in days, weeks and hours. The countdown updates daily based on your current date.
Enter both times in 24-hour format in the Time Between Events calculator. It shows the duration in HH:MM, decimal hours and percentage of the day. Handles overnight spans too.
Use the Duration Converter. Enter hours, minutes and seconds and select 'Total seconds'. For example, 1h 30m 45s = 5,445 seconds. You can also convert seconds back to HH:MM:SS.
The Sleep Calculator shows ideal bedtimes for 3-6 complete sleep cycles (each 90 minutes). For a 7:00 AM wake-up: 6 cycles = 9:46 PM, 5 cycles = 11:16 PM. It includes 14 minutes for falling asleep.
Waking mid-cycle (during deep sleep) causes grogginess. Each 90-minute cycle includes light sleep, deep sleep and REM. Completing full cycles - even fewer of them - leaves you more refreshed than sleeping longer but waking mid-cycle.
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