Rate = APR/12
When I calculated my interest accurately (generally don't because its annoying), I have a rate box and a contribution box in addition to the monthly numbers. The rate box and contribution box are made permanent (use $ symbol, locks the spot in the formula). So its the previous month's balance in parenthesis times the rate plus previous month's balnace minus contribution. =(PM's bal * $X$X)+ PM's bal - $Y$Y YY being the contribution and XX being the rate box. Then drag to populate.
|