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Time Between Dates Calculator

Calculate the exact interval between two dates in several units.

About Time Between Dates Calculator

Converting both dates to a day count makes the difference a simple subtraction and handles leap years and varying month lengths correctly. Months and years are derived from average lengths. Counting days by hand across month boundaries is where date arithmetic usually goes wrong, especially across a February in a leap year.

Formula

Time Between Dates

Days between = day number of the end date − day number of the start date

day number
Days elapsed since 1 January 1970
average month
30.436875 days, allowing for leap years

Worked example

With the default values below, Time Between Dates Calculator returns Days Between of 901. Change any input above and every figure here is recalculated in your browser.

Inputs used

Start date yearaccepts 1,970–2,200
2,024
Start date monthaccepts 1–12
1
Start date dayaccepts 1–31
15
End date yearaccepts 1,970–2,200
2,026
End date monthaccepts 1–12
7
End date dayaccepts 1–31
4

Results

Days Between
901 days
Weeks Between
128.714 weeks
Months Between
29.602 months
Years Between
2.4669 years
Hours Between
21,624 h

Step by step

  1. 1Values used
  2. 2Time Between Dates
  3. 3Days Between= 901 days
  4. 4Weeks Between= 128.714 weeks
  5. 5Months Between= 29.602 months
  6. 6Years Between= 2.4669 years
  7. 7Hours Between= 21,624 h

Assumptions and limits

  • The result is derived only from the 6 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Time Between Dates calculated?

Days between = day number of the end date − day number of the start date Converting both dates to a day count makes the difference a simple subtraction and handles leap years and varying month lengths correctly. Months and years are derived from average lengths.

Why does Time Between Dates matter?

Counting days by hand across month boundaries is where date arithmetic usually goes wrong, especially across a February in a leap year.

What values do I need to enter?

This calculator takes 6 inputs: Start date year, Start date month, Start date day, End date year, End date month, End date day. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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