Time Calculator

Mode

Use 24-hour times. Durations accept HH:MM:SS, HH:MM, or 2.5h. Prefix +/- allowed.

Durations (one per line)

Drag & drop a .txt list here or click to pick a file (nothing is uploaded).

Time Calculator – Quick Cheat Sheet

Add/Subtract: Enter one duration per line. Allowed: HH:MM:SS, HH:MM, or decimal hours with h (e.g., 2.5h). Prefix with + or -.
Time Between: Enter start/end times (24-hour). If end is before start, tick End is next day.
End Time: Provide a start time and a (positive/negative) duration. Result indicates any day offset (e.g., +1 day).
Single numbers in Add/Subtract are treated as hours (e.g., 2 → 02:00:00).
Validation: Times must be HH:MM[:SS] with 00≤MM,SS≤59; durations reject invalid minutes/seconds & formats.
Drag & drop: .txt lists are parsed locally in your browser—no upload occurs.

Edge cases & notes