How to use the Date Calculator
- Choose Days between dates, Add or subtract or Business days.
- Enter the dates. Click (today) to fill in today's date.
- To add time, type the years, months, weeks or days, and choose + Add or − Subtract.
- For business days, pick your working days and add any public holidays to skip.
- Read the result, plus the same span in weeks, months, business days and hours.
How the days are counted
The number of days between two dates counts the nights in between, the way most calendars and contracts do: from Monday to Tuesday is 1 day. Tick Include the end date when both the first and last day count, for example for a hotel booking's length or a holiday from the 1st to the 7th (7 days). From 1 January to 31 December 2027 is 364 days, or 365 with the end date included.
Adding months: why 31 January + 1 month = 28 February
Months have different lengths, so adding a month keeps the same day number where possible and moves to the last day of the month when that day doesn't exist. 31 January plus one month is 28 February (29 February in a leap year), and 31 August plus one month is 30 September. Adding 30 days is not the same as adding 1 month, so pick the one your contract or rule uses.
Business days and holidays
Business days are Monday to Friday unless you change them. In some countries the weekend is Friday and Saturday, so you can pick any working days. Public holidays differ by country and region, so add the ones that apply to you and they're skipped too. Tick Count business days only under Add or subtract to find, for example, the date 10 business days after an order.
Week numbers and day of the year
When you add or subtract time, the result also shows the ISO week number (weeks start on Monday, and week 1 is the week with the year's first Thursday) and the day of the year, such as day 22 of 365.
Frequently asked questions
How many days are there between two dates?
Enter both dates under Days between dates. The result counts from the start date to the end date, not including the end date. Tick Include the end date to count both days.
What is the date 90 days from today?
Choose Add or subtract, leave the start date as today and type 90 in Days. There are ready-made pages too, such as 90 days from today.
How many business days are in a year?
Usually 260 to 262 weekdays, before public holidays. 2026 and 2027 each have 261 weekdays, and 2028 has 260.
Does it handle leap years?
Yes. 29 February is counted in leap years, and adding a year to 29 February lands on 28 February in a year without one.
Can I count backwards?
Yes. Choose − Subtract to find a date in the past, or enter an end date earlier than the start date and the dates are swapped for you.
Are my dates saved?
No. Everything is calculated in your browser and nothing is stored or sent.