Date Difference Calculator
Find the number of days, business days, months, and years between two dates. A free online date calculator that handles leap years automatically — no sign-up, nothing uploaded.
Pick a start and end date to see exactly how much time separates them — useful for countdowns, deadlines, project timelines, or figuring out how long ago something happened. The business-day total counts weekdays only, which is how notice periods and delivery windows are usually written.
How to count the days between two dates
- Pick the start date. Choose the earlier date from the calendar field. The order does not matter — the calculator measures the span either way.
- Pick the end date. Choose the second date. The result appears immediately, with no calculate button to press.
- Read the totals you need. You get the span in years, months, and days, plus totals in days, business days, weeks, and months, and the weekday each date falls on.
Calendar days, business days, and months
Calendar days count every day in the span, weekends and holidays included. This is the figure interest, age, and most deadlines are measured in. The count is exclusive of the start date, so 1 March to 2 March is 1 day.
Business dayscount Monday to Friday only. Over a long span the two diverge sharply — a 30-day month is about 22 business days — which is why a "30 day" and a "30 working day" deadline are more than a week apart.
Months and years are counted as whole calendar units rather than by dividing days by 30 or 365. Months vary from 28 to 31 days, so an averaged figure drifts; stepping through the calendar keeps the answer matching how a contract or a person would count it.
Frequently asked questions
Does the calculator count the difference in days, or years and months too?
Both. The headline is the span in years, months, and days, and below it you get the totals in calendar days, business days, weeks, and months, plus the weekday each date falls on.
Can I calculate the difference between a past date and a future date?
Yes. Either date can be in the past or future — the calculator works out the difference either way.
Is today's date included in the count?
The difference is calculated as full elapsed days between the two dates, so it reflects the actual time span between them. A start and end one day apart counts as 1 day, not 2.
How many business days are between two dates?
The Business days row counts only Monday to Friday, excluding every Saturday and Sunday in the span. It's the figure notice periods, delivery windows, and service-level agreements are usually written in.
Are public holidays excluded from the business day count?
No, deliberately. Public holidays differ by country, state, and year, and a half-correct holiday calendar would be worse than none — it would quietly produce wrong answers for most people. Subtract the holidays that apply to you from the business day total.
Are leap years handled?
Yes. The count uses real calendar dates, so every 29 February inside the span is included. 2024 was a leap year, so 1 January 2024 to 1 January 2025 is 366 days rather than 365.