DATEDIF function - calc no. of months when above 1 year

Within my work I need to know the number of months between two dates. This is so I can know the duration of the grant.

I was hoping to use the DATEDIF function but can't get it to work as the dates are all over 12 months. The function only goes up to 11 months.

If the dates are 12 months or over apart it will just display 0.

for example
01/09/2021
31/08/2023

As the grant runs up to 23:59 on 31/08/2023 the duration for this example grant would be 24 months.
Through Datedif I get 0.

Is there a way to do this through a function?