🧮 Free Calculator
Time Arithmetic Calculator
Enter two durations (A and B) as days, hours, minutes, and seconds — then add or subtract (A − B). Useful for rosters, travel, or study blocks — not for high-precision physics.
✓ No signup ✓ Instant results ✓ Works offline
Durations
Result
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Notes
Negative totals from A − B mean B is longer than A — we still show the absolute span. For clock times on a calendar, combine with our date difference tool.