Savings Goal Calculator

The savings goal calculation solves for one unknown variable given the others. To find the monthly saving needed, it rearranges the future value of an annuity formula: PMT = FV x (r/12) / [((1 + r/12)^(12n) - 1)], where FV is the target amount, r is the annual interest rate, and n is the number of years. This accounts for compound interest on each monthly deposit, giving a lower required saving than simple division of target by months.

To find the time to reach a goal given a fixed monthly saving, the formula is rearranged to solve for n: n = ln(1 + FV x r / (12 x PMT)) / (12 x ln(1 + r/12)). At 0% interest, saving £500/month to reach £30,000 takes exactly 60 months. At 4% AER, compound interest reduces this to approximately 56 months, saving the equivalent of 2 months of contributions.

The calculator also handles lump sum starting balances combined with regular contributions. If you already have £5,000 saved toward a £25,000 goal, the lump sum compounds separately while monthly contributions accumulate. Inflation adjustment shows whether your target amount will have the same purchasing power by the time you reach it — a £30,000 target in 5 years needs to be £34,400 at 2.8% inflation to maintain equivalent value.