Pro-Rata

What Does Pro-Rata Mean?
Used to describe a proportionate allocation. A method of assigning an amount to a fraction, according to its share of the whole. 

Investopedia explains Pro-Rata
For example, a pro-rata dividend means that every shareholder gets an equal proportion for each share he or she owns. Pro-rating also refers to the practice of applying interest rates to different time frames. If the interest rate was 12% per annum, you could pro-rate this number to be 1% a month (12%/12 months).