To use calculator, simply enter Total invested each month, Number of months/years to aquire sum, Interest rate on savings and then click on 'How much will I have?' button to calculate your total savings. The calculator will not accept any characters other than numbers and decimal points, (i.e. commas, dashes, percent signs, dollar signs and etc.). So please do not enter any other characters. To recompute, simply click on 'Clear Form' and start over.