Exceljet

Quick, clean, and to the point

Get months between dates

Excel formula: Get months between dates
Generic formula 
=DATEDIF(start_date,end_date,"m")
Summary 

To calculate months between two dates as a whole number, you can use the DATEDIF function. In the example shown, the formula in D6 is:

=DATEDIF(B6,C6,"m")

Note: DATEDIF automatically rounds down. To round up to the nearest month, see below.

The mystery of DATEDIF

The DATEDIF function is a "compatibility" function that comes from Lotus 1-2-3. For reasons unknown, DATEDIF is only documented in Excel 2000, and will not appear as a suggested function in the formula bar. However, you can use DATEDIF in all curren tExcel versions, you just need to enter the function manually. Excel will not help you with function arguments. See this page on the DATEDIF function for more information about available arguments.

Explanation 

DATEDIF takes 3 arguments: start_date, end_date, and unit. In this case, we want months, so we supply "m" for unit.

DATEDIF automatically calculates and returns a number for months, rounded down.

Nearest whole month

DATEDIF rounds down by default. If you want to calculate months to the nearest whole month, you can make a simple adjustment to the formula:

=DATEDIF(start_date,end_date+15,"m")

This ensures that end dates occurring in the second half of the month are treated like dates in the following month, effectively rounding up the final result.

Author 
Dave Bruns
Related formulas 
Excel formula: Get days between dates
Get days between dates
Dates in Excel are serial numbers that start on 1/1/1900. In the example, the formula in cell D6 simply subtracts the numeric value of 1/1/1999 (36161) from the numeric value of 1/1/2000 (36526) to get a result of 365. The steps look like this: = C6...
Excel formula: Get workdays between dates
Get workdays between dates
The Excel NETWORKDAYS function calculates the number of working days between two dates. NETWORKDAYS automatically excludes weekends (Saturday and Sunday) and can optionally exclude a list of holidays supplied as dates. For example, in the screenshot...
Excel formula: Get days, months, and years between dates
Get days, months, and years between dates
The DATEDIF function is designed to calculate the difference between dates in years, months, and days. There are several variations available (e.g. time in months, time in months ignoring days and years, etc.) and these are set by the "unit"...
Related functions 
Excel DATEDIF function
Excel DATEDIF Function

The Excel DATEDIF function returns the difference between two date values in years, months, or days. The DATEDIF (Date + Dif) function is a "compatibility" function that comes from Lotus 1-2-3. For reasons unknown, it is only documented in Excel...

Excel Formula Training

Formulas are the key to getting things done in Excel. In this accelerated training, you'll learn how to use formulas to manipulate text, work with dates and times, lookup values with VLOOKUP and INDEX & MATCH, count and sum with criteria, dynamically rank values, and create dynamic ranges. You'll also learn how to troubleshoot, trace errors, and fix problems. Instant access. See details here.

500 Formulas | 101 Functions

Download 200+ Excel Shortcuts

Get over 200 Excel shortcuts for Windows and Mac in one handy PDF.