Time Duration Calculator

Time Duration – Quick Cheat Sheet

Inputs: Start and End in YYYY-MM-DDTHH:MM (seconds optional), UTC.
Calendar difference is precise (DateTime::diff()): years → months → days → hours → minutes → seconds.
Totals use absolute seconds between Start and End (UTC) with conversions to minutes/hours/days/weeks.
Swap safety: If End < Start, the tool swaps them and notes it (so you always get a positive duration).
Tip: Use examples to prefill quickly; include seconds if you need second-level accuracy.

Edge cases & notes

UTC avoids DST jumps and timezone ambiguity with datetime-local fields.
Calendar vs totals can differ slightly (e.g., month length variability) — both views are shown.
If Start == End, all totals are zero and calendar diff shows 0 across units.