Savings Goal Calculator

More than almost anything else, because compounding accelerates late. Starting from zero at a steady 7% assumed return, a $1,000,000 goal needs about $1,970 a month over 20 years but roughly $855 a month over 30 — a decade longer more than halves the requirement, since growth covers a larger share of the target. Shortening the horizon works the other way and pushes the monthly figure up sharply. Change the goal, horizon, and return above to see the requirement for your own case.

It depends almost entirely on how long you give it and what return you assume — the monthly amount is not a fixed number. At a 7% assumed return, $1,000,000 needs roughly $1,970 a month over 20 years, about $855 a month over 30 years, and about $405 a month over 40 years. Money already invested reduces all of those, because it compounds for the full horizon. These are arithmetic outcomes of the assumptions you enter, not predictions.

It runs the compound-interest model backwards. Instead of asking what a monthly contribution grows into, it solves for the contribution that lands exactly on your target: required monthly = (goal − starting amount grown to the end) × monthly rate ÷ ((1 + monthly rate) raised to the number of months, minus 1). The annual return is converted to a monthly rate geometrically, so twelve months compound to exactly the annual figure, and contributions are treated as arriving at the end of each month.

There is no correct number, which is why it is an input rather than a fixed value. A steady rate is a simplification: real markets deliver uneven returns, and the order in which good and bad years arrive changes the outcome even when the average is the same. A useful habit is to run the goal at several return assumptions — a cautious one and an optimistic one — and treat the spread between the answers as the real range, rather than relying on any single figure.

Because a target set in future dollars buys less than the same number does today. At 2.5% inflation, $1,000,000 in 20 years has roughly the purchasing power of $610,000 today. Showing both means the goal can be judged in the terms that matter — what it would actually buy — rather than only as a headline number. If you want the target to hold its purchasing power, set the goal higher than the amount you have in mind today.

The required contribution shows as $0, and the calculator reports roughly how long the existing balance alone would take to reach the target under the return you assumed. That is the point some people describe as coasting: no further contributions are needed for the projection to reach the goal on schedule. Contributing anyway would reach it sooner or overshoot it, which the year-by-year table makes visible.

No. The model assumes a steady return, a constant monthly contribution, and no taxes or fees, so it isolates the arithmetic of compounding. Fees and taxes would reduce the real result, meaning the actual contribution needed would be higher than shown. Treat the output as an educational baseline to test assumptions against, not a plan.