Calculate Difference
Raw Units Breakdown
Timeline Overview
Two Honest Ways To Measure Time
There are two correct answers to "how long between these dates", and they rarely match. The calendar difference — 2 years, 3 months, 14 days — is how people naturally think, but it depends on where you start, because months vary from 28 to 31 days. The total difference in days or hours is a single exact number with no ambiguity, which is what you want for billing, SLAs and anything that must be reproducible. Both are shown here rather than picking one, since choosing silently is how off-by-one errors get shipped. Business days count Monday to Friday only and ignore public holidays, which vary by country and can't be assumed.
What else can you check?
These tools all work on the same connection and address data — pick whichever question you actually have.
Date Difference FAQ
Why doesn't "months × 30" match the total days?
Because months aren't 30 days. The calendar difference walks the actual calendar month by month; the total-days figure counts real elapsed days. Both are correct measures of the same interval — they're just answering slightly different questions.
Are public holidays excluded from business days?
No. Business days here means Monday to Friday. Public holidays differ by country, region and sometimes by employer, so assuming a set would produce a confidently wrong number rather than an honest one.
What does "include end date" do?
It adds one day, which is what you want for inclusive ranges — a booking from the 1st to the 5th is 5 days to a hotel but 4 days of elapsed time. Off by default, since elapsed time is the more common need.
Does it handle leap years?
Yes — every figure is counted from the real calendar, so 29 February is included whenever it genuinely falls inside your range. All the maths runs in UTC, which is what keeps a daylight-saving change from silently adding or removing an hour.
Can I calculate someone's age?
Yes — put the birthday in "Start Date", today in "End Date", and read the calendar difference. That gives the same years-months-days figure a passport office would.
