Add up a list of times like 1:30 + 2h45m, find the hours and minutes between two clock times (overnight shifts included), add a duration to a start time, and convert decimal hours to h:mm or 24-hour to 12-hour. No more counting on fingers past 60.
Formats accepted. 1:30 and 1:30:15 (h:mm and h:mm:ss), 1h 30m,
1h30, 90m, 90 min, 45s, 2.5h and plain
2.5 (read as hours). Separate items with + and −, or put one per line — lines
are added. Commas between items also work. Anything it cannot read is listed under the result rather than silently
ignored.
Decimal hours. Payroll systems usually want decimal hours: minutes ÷ 60, so 7:45 is 7.75 and 7:20 is 7.33. The conversion here keeps two decimals; a week of 7:20 days is 36.67 hours, not 36.6. Going the other way, 0.33 hours becomes 20 minutes (19.8 rounded).
Overnight. If the end time is earlier than the start, the calculator assumes you crossed midnight and says so — a 22:00 to 06:00 shift is 8 hours, not −16. Add "extra whole days" for a span longer than 24 hours. The break is subtracted from the total, and a break longer than the shift is flagged rather than producing a negative result.
Clock conversion. Military-style 1530 is read as 15:30; 0000 is midnight
and 2400 is accepted as the end of a day. 12 AM is midnight, 12 PM is noon — the two everybody
gets wrong.