Goal amount, current savings and a target date → the monthly contribution you need, with or without compound interest.
Interest
Assumes contributions are made at the end of each month, and (when included) interest compounds on both your starting balance and your contributions.
About this calculator
This works backwards from a standard savings annuity formula. Your current savings grow on their own to a projected value, and the gap between that and your goal is closed by a series of equal monthly contributions — solved so the total lands exactly on target by your deadline.
With interest included, both your starting balance and every contribution you make keep earning returns for the time remaining until your goal date, so the required monthly amount is lower than a simple, no-interest split of (goal − current savings) over the number of months. Switch compounding frequency between monthly and annually to see how that affects the numbers — more frequent compounding grows the same nominal rate slightly faster.
A few ways to hit a savings goal faster: start as early as possible so compounding has more time to work, automate a fixed transfer right after payday so it isn't optional, and shop around for a better interest rate — even a percentage point or two makes a meaningful difference over several years.
This is a projection based on a constant assumed rate of return, not a guarantee — real interest and investment returns vary over time. Treat the result as a planning estimate rather than financial advice.
Frequently asked questions
Is it better to save a lump sum now or spread it out?
Money invested earlier has longer to earn returns, so a lump sum today generally beats the same amount contributed gradually. That advantage grows with both the interest rate and the time remaining.
What interest rate should I assume?
Use the rate you can actually get on the account or investment you plan to use, and be conservative. Overestimating returns is the quickest way to fall short of a goal, since the required contribution is very sensitive to the assumed rate.