“How many days is that, really?” depends on whether you count the first day, the last day, both, or neither, and most calculators quietly pick one for you.
Free everyday tool
Date Calculator
The days, weeks, months and business days between two dates, or a date shifted by any amount of time.
Runs entirely in your browser. Nothing you enter is sent anywhere.
Inclusive or exclusive: pick the one your situation actually needs
Whether the start and end date both "count" changes the total by exactly one day, and different situations genuinely need different answers. Counting hotel nights, a stay from Monday to Wednesday is 2 nights, exclusive of checkout day. Counting "how many days until," today usually counts as day one, inclusive. Rather than guess, this calculator gives you the toggle and lets the total reflect the question you're actually asking.
Date calculator FAQ
Should I count the start date, the end date, both, or neither?
It genuinely depends on what you're measuring, which is why this calculator gives you the choice instead of picking for you. A hotel stay usually excludes checkout day (you count nights, not days), while "how many days until my exam" usually counts today as day one. The inclusive/exclusive toggle changes the total by exactly one day, small, but it's the exact source of most "why is this off by one" complaints about date calculators.
How are business days calculated?
As every Monday through Friday between the two dates, inclusive of both ends. It does not exclude public holidays, since those vary by country and even by industry, so treat the business-day figure as a weekday count rather than a guaranteed working-day count if your dates span a holiday.
Does this account for leap years?
Yes, automatically and exactly, every date difference is computed from real calendar dates, not an average day-count formula, so a range spanning one or more 29 Februaries comes out correct without any special handling needed from you.
Why does adding "1 month" sometimes land on a different day than I expect?
Because months have different lengths. Adding 1 month to 31 January lands on 28 February (or 29 in a leap year), the last day of February, since there is no 31 February to land on. This calculator clamps to the end of the month in that situation rather than overflowing into March, the same convention most calendar apps use.
Is my data private?
Yes. Every calculation runs in your browser. Nothing you enter is sent to a server.
Free date calculator by ANUPRESS
The one-day gap that causes every complaint
Inclusive and exclusive counting differ by exactly one day, and both are correct, just for different questions. A hotel stay from Monday to Wednesday is 2 nights, exclusive of checkout day. “How many days until the deadline” starting today is usually inclusive, today counts as day one. Rather than silently pick one, this calculator gives you the toggle and lets the total match the question you’re actually asking.
Business days are weekdays, not necessarily working days
The business-day count here means Monday through Friday, nothing more. It deliberately doesn’t try to exclude public holidays, since those vary by country, region, and even industry, and guessing wrong would be worse than not guessing at all. Treat it as a weekday count you can subtract known holidays from yourself, not a guaranteed number of working days.
Adding a month is less obvious than adding a day
Adding 30 days always lands on a definite date. Adding “1 month” is fuzzier, months aren’t the same length, so 31 January plus 1 month has no 31 February to land on. This calculator clamps to the last real day of the target month in that case, the same convention most calendar software uses, rather than overflowing into the following month.