Excel 2016 Month Calculator

Precisely calculate months between dates, add/subtract months, or convert dates to month numbers in Excel 2016 with our interactive tool and expert guide

Calculation Type

Start Date

End Date

Result Format

Full Months (e.g., 5.2)

Rounded Months (e.g., 5)

Excel Formula

Include End Date in Calculation?

Yes

Calculation Results

Total Months: –

Years and Months: –

Exact Days: –

Resulting Date: –

Excel Formula:

–

Comprehensive Guide: How to Calculate Months in Excel 2016

Excel 2016 offers powerful date and time functions that allow you to perform complex month calculations with precision. Whether you need to determine the number of months between two dates, add or subtract months from a date, or extract month numbers for analysis, Excel provides multiple approaches to achieve your goals.

This expert guide covers all essential techniques for month calculations in Excel 2016, including:

Calculating months between two dates (with and without end date inclusion)
Adding and subtracting months from dates while handling month-end scenarios
Extracting month numbers and names from dates
Advanced techniques using DATEDIF, EDATE, and EOMONTH functions
Creating dynamic month-based calculations for financial and project management

1. Understanding Excel’s Date System

Before diving into month calculations, it’s crucial to understand how Excel handles dates:

Excel stores dates as sequential serial numbers (1 = January 1, 1900)
Time is represented as fractional portions of a day (0.5 = 12:00 PM)
Date formatting only affects display, not the underlying value
Excel 2016 supports dates from January 1, 1900 to December 31, 9999

Pro Tip: Always use Excel’s date functions rather than manual calculations to avoid errors with different month lengths and leap years.

2. Calculating Months Between Dates

The most common month calculation is determining the difference between two dates. Excel 2016 provides several methods:

Method 1: Using DATEDIF Function

The DATEDIF function is specifically designed for date differences:

=DATEDIF(start_date, end_date, “m”)
=DATEDIF(start_date, end_date, “ym”)
=DATEDIF(start_date, end_date, “md”)

Example: To calculate months between January 15, 2023 and July 20, 2023:

=DATEDIF(“1/15/2023”, “7/20/2023”, “m”)

Method 2: Using YEAR and MONTH Functions

For more control over the calculation:

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

Example with day adjustment:

=(YEAR(B2)-YEAR(A2))*12 + MONTH(B2)-MONTH(A2) + IF(DAY(B2)>=DAY(A2),0,-1)

Method 3: Using DAYS and DIVIDE

For approximate month calculations:

=DAYS(end_date, start_date)/30

Method	Formula	Result for 1/15/2023 to 7/20/2023	Precision
DATEDIF (“m”)	=DATEDIF(A2,B2,”m”)	6	Complete months only
YEAR/MONTH	=(YEAR(B2)-YEAR(A2))*12 + MONTH(B2)-MONTH(A2)	6	Complete months only
YEAR/MONTH with day adjust	=(YEAR(B2)-YEAR(A2))*12 + MONTH(B2)-MONTH(A2) + IF(DAY(B2)>=DAY(A2),0,-1)	5	Exact months (rounds down)
DAYS/30	=DAYS(B2,A2)/30	6.17	Approximate (30-day months)

3. Adding and Subtracting Months

Excel 2016 provides two primary functions for month arithmetic:

EDATE Function

The EDATE function adds or subtracts months from a date while preserving the day:

=EDATE(start_date, months)

Example: Add 3 months to January 31, 2023:

=EDATE(“1/31/2023”, 3)

EOMONTH Function

The EOMONTH function returns the last day of a month before or after a specified number of months:

=EOMONTH(start_date, months)

Example: Get the last day of the month 2 months after January 15, 2023:

=EOMONTH(“1/15/2023”, 2)

Function	Example	Result	Use Case
EDATE	=EDATE(“1/15/2023”, 3)	4/15/2023	Add months while preserving day
EDATE (negative)	=EDATE(“1/15/2023”, -2)	11/15/2022	Subtract months
EOMONTH	=EOMONTH(“1/15/2023”, 0)	1/31/2023	Get end of current month
EOMONTH	=EOMONTH(“1/15/2023”, 1)	2/28/2023	Get end of next month
EOMONTH (negative)	=EOMONTH(“1/15/2023”, -1)	12/31/2022	Get end of previous month

4. Extracting Month Information

Excel provides several functions to extract month-related information from dates:

MONTH Function

Returns the month number (1-12) from a date:

=MONTH(serial_number)

Example:

=MONTH(“3/15/2023”)

TEXT Function for Month Names

Convert month numbers to names:

=TEXT(date, “mmmm”)
=TEXT(date, “mmm”)

DAY and YEAR Functions

Complement month calculations with day and year extraction:

=DAY(“3/15/2023”)
=YEAR(“3/15/2023”)

5. Advanced Month Calculations

For complex scenarios, combine multiple functions:

Calculating Fiscal Months

Many organizations use fiscal years that don’t align with calendar years. To calculate fiscal months (assuming fiscal year starts in July):

=MOD(MONTH(date)-7+12,12)+1

Age Calculation in Years and Months

Calculate age with precise years and months:

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

Months Until Next Event

Calculate months until a future date (like a contract renewal):

=DATEDIF(TODAY(), event_date, “m”) & ” months until ” & TEXT(event_date, “mmmm d, yyyy”)

6. Handling Edge Cases

Month calculations can become tricky with these scenarios:

Leap years: February 29 in leap years requires special handling
Month-end dates: Adding months to January 31 should return February 28/29
Negative results: When end date is before start date
Blank cells: Handling empty date inputs

Solution for month-end dates: Use EOMONTH to ensure proper handling:

=IF(DAY(start_date)=DAY(EOMONTH(start_date,0)), EOMONTH(start_date, months), EDATE(start_date, months))

7. Practical Applications

Month calculations have numerous real-world applications:

Project Management

Calculating project durations in months
Determining milestone dates by adding months to start dates
Creating Gantt charts with month-based timelines

Financial Analysis

Calculating loan terms in months
Determining investment horizons
Creating month-over-month growth analysis

Human Resources

Calculating employee tenure
Determining probation periods
Scheduling performance reviews

8. Common Errors and Troubleshooting

Avoid these common pitfalls when working with month calculations:

Error	Cause	Solution
#VALUE!	Non-date value in date function	Ensure cells contain valid dates or use DATE function
#NUM!	Invalid date (e.g., February 30)	Use DATE function with valid day parameters
Incorrect month count	Not accounting for day of month	Use day adjustment in formulas (IF(DAY(…)))
Negative months	End date before start date	Use ABS function or swap dates with IF
#NAME?	Misspelled function name	Check function spelling (DATEDIF is correct)

9. Best Practices for Month Calculations

Always validate inputs: Use ISNUMBER or ISTEXT to check date formats
Document your formulas: Add comments explaining complex calculations
Use named ranges: Improve readability with named date ranges
Test edge cases: Verify formulas with month-end dates and leap years
Consider time zones: For international applications, account for time zone differences
Use table references: Convert ranges to tables for dynamic references
Format consistently: Apply uniform date formatting across workbooks
Handle errors gracefully: Use IFERROR to manage potential errors

10. Automating Month Calculations

For repetitive tasks, consider these automation techniques:

Excel Tables

Convert your data range to a table (Ctrl+T) to automatically expand formulas to new rows.

Conditional Formatting

Highlight important month-based dates:

Due dates within 1 month
Anniversaries and milestones
Expiring contracts

Data Validation

Restrict date inputs to valid ranges:

Data Validation → Allow: Date → Between [start_date] and [end_date]

VBA Macros

For complex scenarios, create custom functions:

Function CustomMonthsDiff(start_date As Date, end_date As Date) As Variant ‘ Calculate months between dates with custom logic CustomMonthsDiff = DateDiff(“m”, start_date, end_date) _ – IIf(Day(end_date) < Day(start_date), 1, 0) End Function

Official Microsoft Documentation

For authoritative information on Excel 2016 date functions, refer to:

Academic Resources

For advanced date calculation theories:

NIST Time and Frequency Division – Official time measurement standards
UCAR Center for Science Education – Calendar systems and date calculations

Frequently Asked Questions

Why does DATEDIF sometimes give different results than manual calculations?

DATEDIF uses specific rounding rules:

“m” unit returns complete months between dates
“ym” unit returns months excluding complete years
Results depend on whether you count the start date, end date, or both

How do I calculate months between dates excluding weekends?

Use NETWORKDAYS with a conversion factor:

=NETWORKDAYS(start_date, end_date)/21.67

Can I calculate business months (20 workdays = 1 month)?

Yes, create a custom calculation:

=NETWORKDAYS(start_date, end_date)/20

Why does adding 1 month to January 31 give March 3 in some cases?

This occurs when:

Using simple DATE addition instead of EDATE
The result exceeds the last day of the target month
Solution: Always use EDATE or EOMONTH for month arithmetic

How do I calculate the number of weekdays in a month?

Combine EOMONTH with NETWORKDAYS:

=NETWORKDAYS(DATE(YEAR(date),MONTH(date),1), EOMONTH(date,0))

Conclusion

Mastering month calculations in Excel 2016 opens up powerful possibilities for date-based analysis, project planning, and financial modeling. By understanding the core functions (DATEDIF, EDATE, EOMONTH) and their proper application, you can handle virtually any month-related calculation with precision.

Remember these key points:

Always use Excel’s built-in date functions rather than manual calculations
Account for month-length variations and leap years
Test your formulas with edge cases (month-end dates, negative intervals)
Document complex calculations for future reference
Consider using Excel Tables for dynamic data ranges

For the most accurate results, combine multiple functions as shown in the advanced examples, and always validate your calculations against known benchmarks.

Pro Tip: Create a “date calculator” worksheet in your workbooks with pre-built month calculation formulas for quick reference.