Google Sheets - YEARFRAC function
YEARFRAC function returns the number of fractional years between two days. Syntax YEARFRAC( start_date, end_date, [day_count_convention] ) The day_count_convention is optional and will be ignored in this tutorial. Examples The above result shows that there is 0.497 year between 1/1/2020 and 6/30/2020, or the duration between 1/1/2020 and 6/30/2020 is 49.72%.