Work out the hours and minutes between two times, subtract a break, and get the total as hours:minutes and as decimal hours for a timesheet. Overnight shifts are handled.
Weekly timesheet
How the calculation works
Hours worked = end time − start time − break. If the end time is earlier than the start time, the shift is treated as running past midnight (10 PM to 6 AM is eight hours). Decimal hours divide the minutes by sixty: 7 hours 45 minutes is 7.75, which is what most payroll systems expect. The weekly table saves nothing and sends nothing; it is cleared when you leave the page.
Converting between 12-hour and 24-hour clocks? See the military time chart.
Questions
Will the alarm ring if I close the tab or the laptop?
No. No website can ring after the browser is closed or the computer sleeps. Keep this tab open, plug in, and the clock keeps the screen awake for you. The Ready-to-ring check under the clock shows what is set up correctly.
Does it work on my phone?
Yes on Android while the tab is open (behind other tabs is fine). On iPhone the page must stay in the foreground because Safari does not let web pages play sound from the background. Add it to the Home Screen for a full-screen bedside clock.
Is it loud enough for heavy sleepers?
Pick Loud buzzer or Siren, set the volume slider to full, and switch on the sums-to-stop option in Settings so the alarm cannot be dismissed half asleep. The sunrise light brightens the screen before the alarm too.
Can I use my own sound?
Yes. In Settings, choose an MP3, WAV or OGG file. It is stored in this browser only and never uploaded. There are also 60 built-in sounds, from a twin-bell alarm clock and a rooster to an air horn and a music box, on the sounds page.
What do the sleep sounds do?
Rain, brown noise, white noise, fan and ocean are generated in the browser and play until the alarm, then fade out as it rings. They keep the tab active through the night.
Does it need an internet connection?
Only to load the page the first time. Alarms, sounds, the sleep calculator and the sunrise math all run on your device, and the page works offline once it has been opened.
Is anything stored or sent?
Alarms and settings are saved in your browser's local storage. Nothing is sent to a server, and there is no account.
How do I convert minutes to decimal hours?
Divide the minutes by 60. 15 minutes is 0.25, 30 is 0.5, 45 is 0.75, 20 minutes is 0.33. The calculator shows both forms.
Does it handle overnight shifts?
Yes. An end time earlier than the start time is taken as the next day, so 11 PM to 7 AM gives eight hours.
Is anything saved?
No. Everything is calculated in your browser and nothing is stored or uploaded.