Instant Calculator
Days Between Two Dates

Date Difference Calculator: Find Days Between Any Two Dates

Find out how many seconds there are between two dates. Type in a start and end date below to see right away how many years, months, days, weeks, hours, minutes, and seconds there are between them. This free calculator gives you accurate results without having to worry about leap years. You may use it to keep track of project deadlines, figure out how long an employee has been with the company, or count down to an important event.

Date Difference Calculator

Calculate the difference between two dates in years, months, days, and totals.

The earlier date to compare from.

Defaults to today if left empty.

Enter a start date and an end date to calculate the difference.

How to use this calculator for date differences

It only takes three easy steps to use this calculator. First, choose or type in your start date in the first field. This is the date that comes before the other one. Next, type your end date into the second box. When you click "Calculate," your results show up right away.

The calculator shows your results in two ways. The main result gives the length of time in years, months, and days (for example, 2 years, 4 months, and 15 days). Below that, you'll see the total conversions, which show the total time in months, weeks, days, hours, minutes, and seconds.

What if you put the dates in the wrong order?

No issue. If your end date comes before your start date, the calculator will let you know and still show the absolute difference. This is useful for figuring out how long ago something happened.

Labels for input fields

  • Start Date: The date when your calculation starts (earlier date)
  • End Date: The last day of your computation (later date)
  • Results: Shows years, months, days, and all total conversions

What does it mean to calculate the difference between two dates?

The date difference calculator finds the precise amount of time between two calendar dates. It addresses the most important question: how much time is there between point A and point B on a timeline?

This calculation involves more than just subtracting. Subtracting December 1 from December 15 gives you 14 days. But when you count from January 15 to March 20, you have to remember that February might be 28 or 29 days long, depending on whether it's a leap year, and that other months can be 30 or 31 days long.

Professional date calculations split findings into several units. It might be easier to realize that 432 days is "1 year, 2 months, and 7 days." For project managers who keep count of weeks, that same time frame is "61 weeks and 5 days." For scientists who need to be very exact, it's "10,368 hours" or "622,080 minutes."

How to figure out the difference between two dates by hand

Understanding the math behind date calculations lets you check your work and trust the numbers. This is how professionals do it step by step.

The main formula

The difference between the two dates is the end date minus the start date.

For simple computations in the same month, just subtract the day numbers. From March 5 to March 22 is 17 days (22 - 5 = 17).

How to figure things out across months

January 20 to April 15

  • Days left in January: 31 - 20 = 11 days
  • Full months in between: February (28 days) and March (31 days) add up to 59 days.
  • Days in the last month: 15

The total is 11 + 59 + 15 = 85 days. Two months and 26 days later

Converting to other units

From DaysFormulaExample (100 days)
To WeeksDays / 714 weeks, 2 days
To HoursDays x 242,400 hours
To MinutesDays x 1,440144,000 minutes
To SecondsDays x 86,4008,640,000 seconds

Real-life examples with real numbers

Due Date for the Project Tracking

March 1, 2025, to September 15, 2025

  • Length: 6 months and 14 days
  • Total days: 198 days
  • Total weeks: 28 weeks and 2 days

How to Figure Out How Long an Employee Has Been There

June 15, 2018 to December 21, 2025

  • Length: 7 years, 6 months, and 6 days
  • Total number of months: 90
  • Total days: 2,746 days

Age Calculation

April 3, 1992, to December 21, 2025

  • Age: 33 years, 8 months, and 18 days
  • Total number of days lived: 12,315
  • Total hours: 295,560 hours

Countdown to the Event

December 21, 2025 to August 22, 2026

  • Days until the event: 244 days
  • Weeks until the event: 34 weeks and 6 days

Different ways to keep track of days

Not all day counts are the same. Knowing the differences keeps you from making expensive mistakes at work.

Calendar days, business days, and working days

Every day of the week, including holidays, is a calendar day. A "30-day notice period" that uses calendar days means that there are exactly 30 days on the calendar, including Saturdays and Sundays.

Business days are usually Monday through Friday, not Saturday or Sunday. Some definitions also leave out federal or public holidays. A "30 business days" period usually lasts for more than six calendar weeks.

The number of working days varies by industry and area of law. For certain companies, it matches business days. For people who run 24/7 facilities like hospitals, every day is a work day.

30 Calendar Days Contains (About)Count
Weekdays21-22 days
Weekend days8-9 days
Federal holidays0-3 days (depending on the time of year)
Business days20-22 days (not counting holidays)

Common ways to use date calculations

Human Resources and Employment

Calculating tenure decides who is eligible for retirement benefits, vacation time, and service awards. Most of the time, probationary periods last 90 calendar days from the date of hire.

Legal and Compliance

Attorneys keep track of filing dates, notice periods, and the statute of limitations with great care. There are some rules governing weekends and holidays that apply to court filing deadlines.

Managing a Project

To find out how much the schedule has changed, compare the actual length to the intended duration. Agile techniques use regular 2-week or 4-week cycles for sprint planning.

Healthcare and Medical

Pregnancy tracking counts days from the last menstruation, which is 280 days or 40 weeks. Accurate counting is necessary for medication scheduling.

Things you should not do

Not remembering leap years

A calculation that goes from 2024 to 2028 has two leap years (2024 and 2028), which means that there are two more days compared to years that don't have leap years.

Getting calendar days and business days mixed up

A "10-day deadline" either signify 10 calendar days (approximately 7-8 business days) or 10 business days (14 calendar days). The difference can be quite important.

Thinking that every month has 30 days

January (31), February (28/29), March (31), and April (30) -the differences are important for getting the right numbers.

Not taking into account the different ways dates are written

In the US format, is 03/04/2025 March 4th or April 3rd? Before doing the math, make sure you know the format.

Frequently asked questions

How can I figure out how many days are between two dates?

Put the start and finish dates into the calculator above. It automatically takes the earlier date away from the later date and shows the result in a number of ways, including years, months, days, total weeks, total days, hours, minutes, and seconds. The calculator takes care of leap years and months with different numbers of days on its own.

How do you figure out the difference between two dates?

End Date - Start Date is the basic formula. To figure out the years, months, and days between two dates, first figure out the full years between them, then the full months in the time that is left, and finally the days that are left. The DATEDIF function in Excel does this: =DATEDIF(A1, B1, "Y") for years, "M" for months, and "D" for days.

How do I find out how many business days are between two dates?

Weekends (Saturday and Sunday) are not business days. Count all the days on the calendar between your dates, and then take away the weekends. For instance, a week from Monday to Friday has 5 business days, even though 7 calendar days have passed. You can automatically figure out the number of days between two dates in Excel by using =NETWORKDAYS(start_date, end_date).

Should I count the end date or not when figuring out dates?

It depends on the situation. Include the end date for rental periods, hospital stays, and counting that includes all nights (for example, 3 nights = check-in day through checkout day). When figuring out someone's age, how much time has passed, or most deadlines, don't include the finish date. If you're not sure, ask which strategy is best for your situation.

How do I figure out how many months there between two dates?

Count the full months between the start date and the finish date. It is exactly three months from June 15 to September 15. For months that aren't full, count the entire months first and then write down the extra days. Our calculator automatically shows both full months and the number of days left.

What does the calculator do with leap years?

The calculator automatically finds leap years and changes February to 29 days. Any calculation that goes through February checks to see if that year is divisible by 4 (or 400 if it is a century year). This makes sure that the day counts are correct for durations of more than one year.

What is the difference between working days and calendar days?

Every day on the calendar is a calendar day. Most of the time, working days are merely Monday through Friday, and public holidays are usually not included. There are about 21 to 22 working days in a 30-day calendar. Deadlines set by law or contract should state which method of counting applies.

How do I figure out my precise age in years, months, and days?

Put your birth date as the start date and the date of today as the end date. The calculator shows you just how old you are. For instance, if you were born on March 15, 1990, and today is December 21, 2025, you would be exactly 35 years, 9 months, and 6 days old.

What will happen if I put the end date before the start date?

The calculator finds dates that are in the wrong order and marks them for you. Then it figures out and shows the absolute difference, which is the same amount of time no matter what order the dates are in. This is helpful when figuring out how long ago something happened or when checking that the dates are right.

How can I figure out how long an employee has been with the company since they were hired?

Use the hire date as your start date and today's date (or the finish date) as your end date. The calculator indicates how long someone has worked there in years, months, and days. This is great for HR tasks like figuring out when someone is eligible for benefits, when their pension will vest, and when they will get a service award.

Last changed on December 21, 2025