Investment Calculator

How it's calculated

i = (1 + r)^(1/12) − 1   (r is the yearly return)
FV = S × (1 + i)^m + C × ((1 + i)^m − 1) ÷ i   (× (1 + i) when paid at the start of each month)

Projects a starting sum plus a monthly contribution at a constant yearly return, compounded monthly at the equivalent rate. Over long periods the growth usually outgrows what you put in. Use a cautious rate: past market returns are no promise.