Savings Goal Calculator
Work backward from a savings target: find the monthly contribution you need for a deadline, or how long a fixed monthly amount takes to get there, with compounding included.
Monthly contribution needed
$360
To reach $30,000 in 5 years.
Starting balance
$5,000
Total contributed
$21,625
Growth earned
$3,375
Solving in both directions
A savings plan has four moving parts: the target, what you already have, how much you add each month, and how long you have. Fix any three and the fourth is determined. This calculator solves for the two that people actually ask about.
- Fixed deadline: you know when you need the money — a deposit, a wedding, tuition — and need to know what the monthly commitment is.
- Fixed budget: you know what you can spare each month and want to know when the goal arrives.
If the required monthly figure comes back uncomfortably high, the fix is rarely a higher assumed return. Extending the deadline or lowering the target moves the number far more reliably than optimism about markets.
The formula behind the result
The projection is a future value calculation for an existing balance plus a regular deposit. With P as the starting balance, m the monthly contribution, r the monthly rate (annual ÷ 12), and n the number of months:
FV = P × (1 + r)ⁿ + m × ((1 + r)ⁿ − 1) ÷ rThe first term grows what you already have. The second is the annuity term — each deposit compounds for however many months remain after it lands. Solving that equation for m gives the required contribution; solving it for n with logarithms gives the time to target.
Contributions are assumed to arrive at the end of each month, which is the conservative convention. Depositing at the start of each month instead gives every contribution one extra month of growth and produces a slightly better result.
Choosing a realistic return
The return you assume should follow the timeline, not the ambition. Money needed soon cannot be exposed to assets that might be down when you need it.
| Timeline | Typical vehicle | Reasonable assumption |
|---|---|---|
| Under 1 year | Checking, cash | 0% |
| 1–3 years | High-yield savings, term deposit | 2–4% |
| 3–7 years | Bonds, mixed portfolio | 3–5% |
| 7+ years | Diversified equities | 5–7% |
Tip: set the rate to 0% once to see the plan with no market help at all. If the monthly figure still works, the goal is safe regardless of what returns do.
When contributions matter more than returns
The growth bar in the results makes a point worth internalizing: over short horizons, almost the entire balance is money you put in. Compounding needs time before it contributes meaningfully, and on a three-year goal there simply is not enough of it.
This flips somewhere around the fifteen to twenty year mark, where growth can exceed total contributions. For a house deposit or a car, the contribution rate is effectively the whole plan. For retirement, the starting date matters more than the monthly amount.
Scope and limitations
This is a deterministic projection at a constant rate. Real returns vary year to year, and a sequence of poor early years leaves you short of a figure that a steady-average calculation promised. It also ignores inflation, so a target set today buys less by the time you reach it — for long horizons, consider raising the target or entering a real (inflation-adjusted) return instead of a nominal one.
Taxes on interest or gains, account fees, contribution limits on tax-advantaged accounts, and employer matching are all excluded. Treat the output as a planning baseline rather than a guarantee, and revisit it as your income and the goal change.