Is there a standard Day/Month proration for Rentals

[Daniel Dube]

Hey team,

I was just wondering if there is a standard number of days used to calculate daily rent proration or is it based on the actual month it's in?

This month being 28 days means each day costs more than a 31 day month, but I don't want to look like an amateur if everyone uses 30 days as a standard month length. 

Thanks,