Time calculator
Time Between Two Dates Calculator
Count the exact number of days between any two dates and see the span in years, months, weeks, weekdays, hours, minutes, and seconds.
Total days
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How the Time Between Two Dates Calculator works
Enter a start date and an end date to see the elapsed calendar time and equivalent totals. The calculator treats each date as midnight in UTC, so daylight saving changes and local time zones cannot add or remove an hour from the result.
Date difference formula
Years, months, and days are calculated as calendar units rather than averages. Whole years are counted first, then whole months, then the days left over. This respects leap years and the actual length of every month.
Inclusive and exclusive date counting
By default, the result is exclusive of the end date. For example, Monday to Tuesday is one elapsed day. Select Include end date when both boundary dates should count, such as when measuring a trip or event that takes place on every listed date.
Weekdays and weekend days
Weekdays are Monday through Friday, while weekend days are Saturday and Sunday. These totals do not exclude public holidays, because holiday calendars differ by country and region.
Example: August 20 to December 25, 2026
From August 20, 2026 to December 25, 2026 there are 127 elapsed days. That is 18 full weeks and 1 remaining day. Including December 25 changes the total to 128 days.
Frequently asked questions
How many days are between two dates?
Subtract the earlier date from the later date after normalizing both to the same time zone. Calquo performs this calculation in UTC and shows the result in total days.
How do I include the end date?
Select Include end date. One day is added to the elapsed interval, and all totals update immediately.
How many weekdays are between two dates?
The weekday result counts Mondays through Fridays in the selected interval. Saturdays and Sundays appear separately as weekend days.
Does the calculator account for leap years?
Yes. It uses the real Gregorian calendar, including February 29 in leap years and the correct length of every month.
Why can months not be converted to a fixed number of days?
Calendar months range from 28 to 31 days. The months result uses the actual dates, while total days provides a fixed-unit duration.
Does daylight saving time affect the result?
No. Dates are normalized to UTC before calculation, preventing daylight saving changes from causing off-by-one errors.
How the date difference calculator works
Pick a start date and an end date. The calculator counts the whole days between them and then expresses that span in every common unit: a calendar difference in years, months, and days; full weeks with leftover days; total hours, minutes, and seconds; and a split between weekdays (Monday through Friday) and weekend days. The end date must be the same as or later than the start date, and the tool tells you if the two are reversed.
By default the count runs from the start date up to, but not including, the end date, which is how most people count the days until an event. Tick the Include end date box to add one more day so both dates count, which is how you would count the days of a vacation, a rental period, or a contract term.
How the numbers are calculated
Take January 15, 2026 to April 10, 2026. January 15 to February 15 is 31 days, February 15 to March 15 is 28 days, and March 15 to April 10 is 26 days, for a total of 85 days. That is 12 full weeks and 1 day, 2,040 hours, 122,400 minutes, and 7,344,000 seconds. The calendar difference is 0 years, 2 months, and 26 days. Including the end date makes it 86 days, which is 12 weeks and 2 days, or 2 months and 27 days.
Because January 15, 2026 falls on a Thursday, those 85 days contain 61 weekdays and 24 weekend days: 12 full weeks give 60 weekdays and 24 weekend days, and the one leftover day is a Thursday.
Calendar difference versus total days
Total days is an exact count. The years, months, and days figure is a calendar reading that depends on where the span starts, because months are not the same length. The calculator anchors on the start date, steps forward in whole years, then whole months, and counts whatever is left over as days. If a step would land on a day that does not exist, such as the 31st of a 30-day month, it uses the last day of that month instead.
That is why January 31 to March 1, 2026 reads as 29 days but also as 1 month and 1 day: one month after January 31 is treated as February 28, leaving a single day to reach March 1. Starting the same 29-day span from a different date would give a different month-and-day reading. For contracts, billing, and anything where precision matters, rely on the total days.
When to include the end date
Whether the end date counts depends on what you are measuring. If you are counting down to a date, or measuring nights between check-in and check-out, leave the box unchecked. If both the first and last day are part of the period, check it.
- Days until a deadline, birthday, or trip: exclude the end date
- Hotel nights or rental days billed per night: exclude the end date
- Days of paid leave, a course, or a project where the last day is a working day: include the end date
- Lease or contract length stated as running from one date through another: include the end date
- Age or tenure in years and months: exclude the end date and read the calendar difference
Weekdays, leap years, and what the tool does not do
The weekday count treats every Monday through Friday as a weekday, starting with the start date itself. It does not know about public holidays, company closures, or half days, so subtract those yourself if you need a true business-day count. Weekend days are simply the total minus the weekdays.
Leap years are handled: February 29, 2024 counts as a day, so January 1, 2024 to January 1, 2025 is 366 days. All arithmetic is done on calendar dates at midnight, so daylight saving time changes and time zones do not affect the result, and the hours, minutes, and seconds figures are exact multiples of whole days rather than clock-time differences between two specific moments.
Frequently asked questions
How do I count the days between two dates?
Subtract the start date from the end date. January 1, 2026 to December 31, 2026 is 364 days, or 365 if you include the end date. The calculator does the subtraction across month and year boundaries for you.
Should I include the end date?
Include it when both the first and last day belong to the period, such as days of leave or the length of a contract. Leave it out when counting down to an event or counting nights between two dates.
How does the calculator count months between dates?
It steps forward from the start date in whole years, then whole months, and reports the leftover days. If a month step lands on a date that does not exist, it uses the last day of that month, so January 31 plus one month is February 28 or 29.
Does it count business days?
It counts weekdays, meaning every Monday through Friday in the span. It does not exclude public holidays, so subtract any holidays that fall in your range to get a business-day count.
Does the calculator account for leap years?
Yes. February 29 is counted whenever the span crosses it in a leap year. From January 1, 2024 to January 1, 2025 is 366 days, while the same span in 2025 is 365 days.
How many weeks are between two dates?
Divide the total days by 7. The calculator shows the whole weeks and the days left over, so 85 days is 12 weeks and 1 day.