Prorate

[prəʊ'reɪt;'prəʊ-] or ['proret]

(verb.) divide or assess proportionally; 'The rent was prorated for the rest of the month'.

(verb.) make a proportional settlement or distribution.

Checked by Lionel--From WordNet

(v. t.) To divide or distribute proportionally; to assess pro rata.

Typed by Jared