Excel Months Between Dates Calculator

Calculate the exact number of months between any date and today with precision

Total Months: 0

Years and Months: 0 years, 0 months

Exact Days: 0 days

Excel Formula: =DATEDIF(A1,TODAY(),”m”)

Complete Guide: How to Calculate Number of Months Between Dates in Excel

Calculating the number of months between two dates is a common requirement in financial analysis, project management, and data reporting. Excel provides several methods to accomplish this, each with different levels of precision. This comprehensive guide will explore all available techniques, their advantages, and practical applications.

The DATEDIF Function: Excel’s Hidden Gem

The DATEDIF function is Excel’s most powerful tool for date calculations, though it’s not officially documented in Excel’s function library. This “hidden” function can calculate the difference between two dates in years, months, or days with various levels of precision.

DATEDIF Syntax and Parameters

The basic syntax for DATEDIF is:

=DATEDIF(start_date, end_date, unit)

Where:

start_date: The beginning date of the period
end_date: The ending date of the period
unit: The type of information to return:
- “Y” – Complete years between dates
- “M” – Complete months between dates
- “D” – Complete days between dates
- “MD” – Days between dates (ignoring months and years)
- “YM” – Months between dates (ignoring days and years)
- “YD” – Days between dates (ignoring years)

Practical Examples of DATEDIF

Let’s examine how to use DATEDIF for different scenarios:

Basic month calculation:
```
=DATEDIF("1/15/2020", TODAY(), "m")
```
Returns the total number of complete months between January 15, 2020 and today.
Years and months separately:
```
=DATEDIF("5/3/2018", TODAY(), "y") & " years, " & DATEDIF("5/3/2018", TODAY(), "ym") & " months"
```
Returns something like “3 years, 4 months” for the period between May 3, 2018 and today.
Exact days remaining in current month:
```
=DATEDIF(TODAY(), EOMONTH(TODAY(),0), "d")
```
Calculates how many days remain until the end of the current month.

Alternative Methods for Month Calculations

While DATEDIF is the most comprehensive solution, Excel offers several alternative approaches for calculating months between dates:

Using YEAR and MONTH Functions

For simple month calculations, you can combine the YEAR and MONTH functions:

= (YEAR(end_date)-YEAR(start_date))*12 + MONTH(end_date)-MONTH(start_date)

This formula calculates the total months by:

Finding the difference in years and multiplying by 12
Adding the difference in months

Method	Formula Example	Precision	Handles Leap Years	Handles Partial Months
DATEDIF	=DATEDIF(A1,B1,”m”)	High	Yes	Configurable
YEAR/MONTH	= (YEAR(B1)-YEAR(A1))*12 + MONTH(B1)-MONTH(A1)	Medium	No	No
EDATE	=MONTH(EDATE(A1,B1)-A1)	Medium	Yes	No
Days/30	= (B1-A1)/30	Low	No	Yes (as decimal)

Using the EDATE Function

The EDATE function can help calculate months between dates by finding how many months you need to add to the start date to reach the end date:

=MONTH(EDATE(start_date, months_to_add)-start_date)

However, a more practical approach is:

= (YEAR(end_date)-YEAR(start_date))*12 + MONTH(end_date)-MONTH(start_date) - IF(DAY(end_date)<DAY(start_date),1,0)

This adjusted formula accounts for cases where the end day is earlier than the start day.

Handling Edge Cases and Special Scenarios

Real-world date calculations often involve special cases that require careful handling:

Dealing with the 31st of the Month

When calculating months between dates where one date is the 31st, Excel may produce unexpected results because not all months have 31 days. For example:

=DATEDIF("1/31/2023", "3/1/2023", "m")

This returns 0 months because February doesn’t have a 31st day. To handle this:

=DATEDIF(start_date, EOMONTH(start_date,0), "d")

Calculating Business Months

For financial calculations where you need to count only business days (excluding weekends and holidays):

=NETWORKDAYS.INTL(start_date, end_date, [weekend], [holidays])/30

Then multiply by 30 to approximate business months.

Working with Fiscal Years

Many organizations use fiscal years that don’t align with calendar years. To calculate months between dates in a fiscal year (e.g., starting July 1):

= (YEAR(end_date)+(MONTH(end_date)>=7)) - (YEAR(start_date)+(MONTH(start_date)>=7)))*12 +
     (MONTH(end_date)-IF(MONTH(end_date)>=7,MONTH(end_date)-6,MONTH(end_date)+6)) -
     (MONTH(start_date)-IF(MONTH(start_date)>=7,MONTH(start_date)-6,MONTH(start_date)+6))

Visualizing Date Differences with Charts

Creating visual representations of time periods can help communicate date differences more effectively. Excel offers several chart types suitable for displaying month calculations:

Gantt Charts for Project Timelines

To create a Gantt chart showing months between dates:

Create a table with start dates, end dates, and duration in months
Insert a stacked bar chart
Format the start date series to have no fill
Adjust the duration bars to show the time period

Timeline Charts

For showing multiple date ranges:

Use a scatter plot with date axis
Add error bars to represent durations
Customize colors for different categories

Advanced Techniques for Power Users

For complex scenarios, consider these advanced approaches:

Array Formulas for Multiple Date Ranges

To calculate months between multiple date pairs in one formula:

{=SUM(DATEDIF(start_range, end_range, "m"))}

Enter this as an array formula with Ctrl+Shift+Enter in older Excel versions.

Power Query for Large Datasets

For analyzing thousands of date pairs:

Load data into Power Query

Add a custom column with formula:

= Duration.Days([End Date] - [Start Date])/30

Load back to Excel

VBA for Custom Solutions

Create a custom function for specialized calculations:

Function MonthsBetween(start_date As Date, end_date As Date, Optional method As String = "exact") As Variant
    ' Custom month calculation logic here
    End Function

Common Mistakes and How to Avoid Them

Even experienced Excel users make these common errors when calculating months between dates:

Mistake	Example	Problem	Solution
Using simple subtraction	=B1-A1	Returns days, not months	Use DATEDIF with “m” unit
Ignoring day of month	= (YEAR(B1)-YEAR(A1))*12 + MONTH(B1)-MONTH(A1)	May overcount by 1 month	Add DAY() comparison adjustment
Assuming 30 days = 1 month	= (B1-A1)/30	Inaccurate for precise calculations	Use DATEDIF for exact months
Not handling #NUM! errors	=DATEDIF(B1,A1,”m”) where B1 < A1	Returns error if dates reversed	Use IFERROR or date validation
Forgetting about time zones	Dates from different systems	May cause off-by-one errors	Standardize to UTC or local time

Real-World Applications

Understanding how to calculate months between dates has practical applications across many fields:

Financial Analysis

Calculating loan terms in months
Determining investment holding periods
Analyzing revenue growth over specific month periods

Human Resources

Tracking employee tenure
Calculating vesting periods for benefits
Managing probation periods

Project Management

Creating accurate project timelines
Monitoring milestone achievements
Calculating buffer periods between phases

Legal and Compliance

Tracking contract durations
Calculating statute of limitations periods
Managing regulatory filing deadlines

Best Practices for Reliable Date Calculations

Follow these guidelines to ensure accurate and maintainable date calculations:

Always validate inputs: Use data validation to ensure cells contain proper dates
Document your formulas: Add comments explaining complex calculations
Test edge cases: Verify with dates at month/year boundaries
Consider time zones: Be consistent about whether dates include time components
Use named ranges: Make formulas more readable with descriptive names
Handle errors gracefully: Use IFERROR to provide meaningful error messages
Consider leap years: Especially important for long-term calculations
Format consistently: Use the same date format throughout your workbook

Learning Resources and Further Reading

To deepen your understanding of Excel date functions, explore these authoritative resources:

Frequently Asked Questions

Why does Excel sometimes give different results than manual calculations?

Excel handles date serial numbers differently than manual calculations in several ways:

Excel counts February 29 in leap years as a valid date
Excel’s date system starts from January 1, 1900 (Windows) or 1904 (Mac)
Excel uses banker’s rounding for some calculations
Time components (even midnight) can affect some calculations

How can I calculate months between dates excluding weekends?

Use this formula combination:

=NETWORKDAYS(start_date, end_date)/30

For more precision, create a custom function that counts only weekdays when determining complete months.

What’s the most accurate way to calculate age in years and months?

This formula provides the most accurate age calculation:

=DATEDIF(birth_date, TODAY(), "y") & " years, " & DATEDIF(birth_date, TODAY(), "ym") & " months"

For even more precision including days:

=DATEDIF(birth_date, TODAY(), "y") & " years, " & DATEDIF(birth_date, TODAY(), "ym") & " months, " & DATEDIF(birth_date, TODAY(), "md") & " days"

How do I handle dates before 1900 in Excel?

Excel’s date system doesn’t support dates before January 1, 1900 (Windows) or 1904 (Mac). For historical dates:

Store as text and parse manually
Use a custom date system with a different epoch
Consider specialized historical date libraries

Can I calculate months between dates in Excel Online?

Yes, all the functions mentioned (DATEDIF, YEAR, MONTH, etc.) work in Excel Online with the same syntax. The main differences are:

Some array formula entry methods differ
Power Query is available but with slightly different interface
VBA/macros aren’t supported in the online version

Excel Calculate Number Of Months Between Date And Today