Pro Rata Calculator Pro Rata Calculator Total Amount ($): Total Period: Actual Used Period: Days Weeks Hours Tax Rate (%): Include Tax Calculate How to Use the Pro Rata Calculator 1. Enter the total amount in dollars in the "Total Amount" field. This is the full amount you want to calculate the pro rata portion of. 2. Enter the total period in the "Total Period" field. This represents the total duration (in days, weeks, or hours) over which the total amount applies. 3. Enter the actual used period in the "Actual Used Period"...