Date & Time

Date Difference Calculator

Measures the gap between pairs of dates in calendar terms and in plain totals, both at once.

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How to use this tool

  1. Put two dates on each line, separated by a comma, a tab, an arrow or the word "to".
  2. Select Measure.
  3. Use the calendar column for anything a person will read, and the day total for anything a contract or a calculation depends on.

What date difference does

There are two honest answers to "how far apart are these dates", and this page gives both. The calendar breakdown counts whole years and months the way a person does, so 31 January to 4 March is two years and one month and a day rather than a number divided by thirty. The totals column counts actual elapsed days, which is what an SLA or an interest calculation needs.

Put both dates on one line, separated by a comma, a tab, an arrow or the word "to", and paste as many lines as you like. That shape means a two-column export out of a spreadsheet goes straight in, which is where most of these questions come from — a list of start and end dates that somebody needs turned into durations.

Frequently asked questions

Because months are not thirty days. The breakdown counts whole calendar months the way a person would — 31 January to 28 February is one month, not 28 days over 30 — and then the leftover days. Both answers are correct for different questions, so both are shown.

No. The day count is the elapsed gap, so 1 March to 2 March is one day. If you need inclusive counting — for a hire period or a stay — add one. The business day calculator counts inclusively instead, because that is the convention there.

A comma, a tab, a pipe, an arrow, or the word "to" all work. The tab case matters most in practice, because it means two columns copied straight out of a spreadsheet paste in without editing.