Microsoft Excel - To calculate total years of experience based on two dates

[1] Resume

company 1  -- worked  from SEP 05 to Oct 05
company 2 -- worked from Jan 06 to Dec 06

total expr is 1 year 2 month

can somebody help on this? Which type of formula to use?

The DATEDIF() formula will calculate the number of days, months, or years between two dates. ( Reference: Excel Help)

I used the date ranges of:
    9/1/2026 - 11/1/2026
    1/1/2026 - 1/1/2026

When I used the date of 1 day earlier, it didn't have the same ideal result.

So, the formula, with  A1 =  9/1/2005, B1 = 11/1/2005, A2 = 1/1/2006, & B2 = 1/1/2026

=CONCATENATE(SUM( DATEDIF( A1, B1, "y" ), DATEDIF( A2, B2, "y" )), " years, ", SUM( DATEDIF( A1, B1, "ym" ), DATEDIF( A2, B2, "ym" )), " months, ", SUM( DATEDIF( A1, B1, "md" ), DATEDIF( A2, B2, "md" )), " days.")

This will return "1 years, 2 months, 0 days."

If you simply write SEP 05 without the day part, it will be considered as 01-09-2025

Assuming the values you have mentioned are placed in these cells -
A1 = SEP 05  
B1 = Oct 05
A2 = Jan 06  
B2 = Dec 06

Try this formula to get the total in months.
=SUM(ROUND((A1-B1)/30,0),ROUND((A2-B2)/30,0))