Date & time Difference

Duration between dates

From

Counting

Duration —

The same gap in other units

Days —

Weeks —

Whole weeks —

Months —

Years —

Hours —

Minutes —

Note Enter both dates

Calendar breakdown first, totals below

A duration is the same span expressed in whichever unit suits it. Under a week, days. Under a year, weeks or months. Beyond that, years and months. The calendar breakdown at the top always reads naturally; the totals underneath are for calculations.

How to describe a duration

1 Enter the start and end dates.

2 Read the natural breakdown first.

3 Pick whichever total unit your calculation needs.

4 Include both days if the duration is something you occupy.

Choosing the unit is a communication decision rather than an arithmetic one. "Nine hundred days" and "two years five months" describe the same span, and they land very differently — the first sounds like an endurance, the second like a plan. Reports and contracts generally want the calendar form; countdowns and progress bars want the smallest unit that still moves visibly.

Questions

What is the best unit for a duration? −

The largest one that still conveys precision. Years and months for long spans, days for anything under a month.

Why does the same span sound different by unit? +

Should the end day count? +

How is the calendar breakdown worked out? +

Does it handle spans across leap years? +

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