The amount payable usually paid as prorate. A pro rata premium is simply a proportional premium. This is typically a once-off premium, only covering the unusual time period.
Policy start date 15 June. Suppose - The annual premium for the policy is Rs 5000. The pro rata premium for June is calculated as follows:-
5000 divided by 365(days in a year) and multiplied by 210 (remaining days in year [roughly]). The pro rata premium would be Rs 2876.71.