📆 Pick Your Dates
Quick:
Date Difference Calculator
How long between two dates — in calendar terms and in raw units, with business days counted separately. Or move forward and back from a date by any amount.
➕ Move From A Date
📌 About calendar maths. "1 month" isn't a fixed length — from 31 January, adding a month lands on 28 or 29 February, not 31 February. This calculator clamps to the last valid day of the target month, which is what almost every date library and billing system does. The total-days figure is always exact regardless.
HOW IT WORKS
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.
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Announced prefixes, BGP neighbours and registry details.
Want to test your connection speed?
Measure real download, upload, ping and jitter.
Want to see what changed?
Word-level diff between two blocks of text or code.
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 "count the end day too" 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 and daylight saving?
Leap years, yes — they're counted from the real calendar. Daylight saving is handled for the date maths, but if a clock change falls inside your range the hours figure can be off by one relative to wall-clock time, which is inherent to the concept rather than an error here.
Can I calculate someone's age?
Yes — put the birthday in "From", today in "To", and read the calendar difference. The "Age from birthday" quick button sets that up for you.