How this works
Pick a target amount, a timeline, and an expected rate of return — this calculator solves for the monthly contribution that lands you exactly there. Existing savings get factored in: they keep growing on their own, so the gap your contributions need to fill is smaller than it first looks. The result also splits the future balance into your contributions vs. interest earned, so you can see how much of the work the market is doing for you.
The formula
C = monthly contribution. FV = savings goal (future value). P = current savings. r = monthly rate (annual rate ÷ 12, as a decimal). n = total months (years × 12). When the rate is zero, the formula simplifies to C = (FV − P) / n.
Example calculation
- Goal: $50,000 down payment in 5 years. You already have $5,000 saved and expect 5% annual return.
- Your $5,000 grows to about $6,420 on its own. The remaining ~$43,580 has to come from monthly contributions over 60 months.
- Required contribution: about $640/month. Over 5 years you contribute ~$38,400; the rest (~$5,180) comes from interest.
Frequently asked questions
What if I can't afford the suggested monthly amount?
You have three levers: stretch the timeline, lower the goal, or raise expected return (which usually means more risk). Even a small extension helps a lot — pushing a 5-year goal to 7 years can drop the required monthly contribution by 30–40%, since you get more contributions and more interest.
Should I include emergency savings in this goal?
Probably not. Emergency funds need to be liquid and stable — typically held in a high-yield savings account. Calculate them separately (3–6 months of expenses) and treat investing goals as money you can leave alone. Mixing the two leads to dipping into investments at the worst possible moment.
Why does the result come out as zero?
It means your existing savings, growing at the rate you entered, will already exceed the goal by the end of the timeline — so no further contributions are needed. Lower the rate of return, raise the goal, or shorten the timeline to see a non-zero monthly target.
Should I use a single monthly amount or front-load contributions?
Mathematically, earlier money compounds longer, so front-loading wins on a long horizon. Practically, dollar-cost averaging (a steady amount each month) reduces the risk of investing all your money right before a downturn and is much easier to stick with. For most people, consistency beats optimization.