Date Calculator: Days Between Dates and Date Adder
Our date calculator counts the days between dates and splits the gap into years, months, weeks and working days. It also adds or subtracts days, weeks, months or years from any date. Pick two dates or a start date to see the result.
What a Date Calculator Does
A date calculator works out the time between two calendar dates or finds a new date from a starting point. People use one to count down to a holiday, track a notice period or check how long a project ran. Doing it by hand is slow because months have 28, 29, 30 or 31 days.
Our tool also works as a date difference calculator and shows the gap in several forms at once. You get total days, weeks and days, months and days and a full years, months and days breakdown. It also counts working days, weekend days, hours and minutes.
How to Use the Date Calculator
- Choose Count the time between two dates, then pick a start date and an end date.
- Tick Include the end date if both the first and the last day should count.
- Choose Add or subtract time from a date to find a deadline or a past date.
- Enter years, months, weeks and days in any mix, then read the result date.
Results update the moment you change a date. If the end date comes before the start date, the tool swaps them and tells you. The date boxes use your device's calendar picker, so the format follows your own settings.
How to Count Days Between Dates
The simplest way to find the days between dates subtracts the start date from the end date. The tool turns both dates into a count of days from a fixed point and takes the difference, which avoids month length mistakes. For January 1, 2026 to December 31, 2026, it returns 364 days.
Should You Include the End Date?
By default the start date counts as day 0, the same way a hotel counts nights. A stay from Monday to Friday is 4 nights. If you need every calendar day, such as days of leave, tick the box and the 2026 example becomes 365 days.
Counting Months and Years
Months are uneven, so the years, months and days figure counts whole calendar months first and then the days left over. From January 31 to March 1, 2026 the result is 1 month and 1 day, because one month after January 31 lands on February 28. Other tools may treat this edge case in their own way, so check short gaps around month ends with care.
Days Between Dates in Common Periods
The table below shows the days between dates for a few periods people often check. Each figure comes from the tool with the end date left out. Use them as a quick reference when you plan ahead.
| Period | Days |
| January 1 to December 31, 2026 | 364 |
| January 1, 2026 to January 1, 2027 | 365 |
| January 1, 2024 to January 1, 2025 | 366 |
| June 1 to August 31, 2026 | 91 |
| October 2 to December 25, 2026 | 84 |
Notice how the totals change with month length even when two gaps look the same on paper. February always makes a one month gap shorter. Leap years add one extra day to any period that crosses February 29.
Working Days and Weekends
The business days figure counts Monday to Friday and skips Saturdays and Sundays. It counts the start date but not the end date, unless you tick the box. Over all of 2026, with the end date included, the tool finds 261 working days and 104 weekend days.
Public holidays differ by country and even by state, so the tool leaves them in. Subtract your local holidays to get a payroll or delivery figure. The 11 US federal holidays all fall on weekdays when observed in 2026, which brings that year down to 250 working days.
How to Add Days to a Date
To add days to a date, pick the start date, choose Add and type the number of days. Ninety days after October 2, 2026 is Thursday, December 31, 2026. Contracts, visas and return windows often use day counts like this, so the exact weekday matters.
Months and years work differently from days. Adding 1 month to January 31 gives February 28, because February has no 31st, and the tool tells you when this happens. Adding 1 year to February 29, 2024 gives February 28, 2025 for the same reason.
Subtracting works the same way in reverse. Pick Subtract to find a start date from a deadline, such as the last day to post a parcel. You can mix years, months, weeks and days in one step.
Days Until an Event
A countdown is simply the days between dates with today as the start. From October 2, 2026, Christmas Day is 84 days away. Set the end date to a birthday, a wedding or an exam and the date calculator gives the same kind of answer.
For your exact age, our Age Calculator gives years, months and days from a birth date. For pregnancy timing, the Pregnancy Due Date Calculator counts weeks from the last period. Both follow the same calendar rules as this page.
Leap Years and Calendar Rules
A leap year adds February 29 to keep the calendar in line with the seasons. Years divisible by 4 are leap years, except century years, which must also divide by 400. That is why 2000 had a February 29 and 2100 will not.
The tool follows the Gregorian calendar for every date, including dates before it was adopted in 1582. Historians who work with older Julian dates should convert them first. For everyday dates from 1900 onward, this makes no difference.
Common Uses
- Counting the days left on a contract, lease or warranty.
- Working out a notice period or a probation end date.
- Planning project timelines and sprint lengths in weeks.
- Checking how long ago an event happened, such as a purchase or a move.
Tips for Accurate Results
Before you count the days between dates, decide whether your rule counts the first day, the last day or both. Legal and HR deadlines often state this, so read the wording before you trust any number. When a result lands on a weekend, many deadlines move to the next working day.
Time zones do not affect this tool because it works with whole calendar days. A flight that leaves on one date and lands on the next still counts as one day apart. For hour level timing across zones, use a time zone converter.
Why Use Our Date Calculator
It counts the days between dates, splits them into useful units and finds future or past dates in one place. Working days, weekends and month end rules are all handled for you. Everything runs in your browser and nothing you enter is stored. Pick your dates and count your days now.
Frequently asked questions
Is this date calculator free?
Yes, it is free with no sign up and no limit.
How many days are in 2026?
There are 365, because 2026 is not a leap year.
Does the date difference calculator count weekends?
Yes, it shows working days and weekend days separately.
Are business days the same as working days?
Here they mean Monday to Friday, with public holidays left in.
How many days until Christmas?
From October 2, 2026, Christmas Day is 84 days away.
Can I count the days between dates in different years?
Yes, any two dates from year 1 to 9999 work.
Does the date calculator include the end date?
Only when you tick the Include the end date box.
Related calculators
Other tools people use alongside the date difference calculator.