Savings Calculator
Calculate how long it will take to reach your savings goal, given a starting balance, monthly deposit, and annual interest rate — with a projected balance and growth breakdown.
How It's Calculated
Formula
FV = P\left(1+\dfrac{r}{12}\right)^{n} + PMT\left[\dfrac{\left(1+\dfrac{r}{12}\right)^{n}-1}{r/12}\right]This calculator works out how long it will take to reach a savings goal, given a starting balance, a fixed monthly deposit, and an annual interest rate compounded monthly. Each monthly deposit is applied at the end of that month (an "ordinary annuity"), so a deposit made in the current month doesn't start earning interest until the next one. Rather than assuming a fixed time period, this calculator searches month by month for the first month your balance reaches (or exceeds) your goal, then reports your projected balance, total deposits, and total interest earned at that exact point. If your current balance, deposit, and interest rate together can never reach your goal — for example, a $0 deposit with a $0 interest rate and a goal above your starting balance — the calculator says so explicitly rather than showing a misleading estimate.
Worked Examples
Ordinary case: $1,000 starting balance, $200/month, 6% annual rate, $10,000 goal
- Balance grows monthly at a periodic rate of 6%/12 = 0.5%, plus a $200 deposit at the end of each month
- The calculator checks each month's balance until it first reaches $10,000
- Total deposits and total interest earned are reported at that exact month, not an approximation
Contributions only: $0 starting balance, $300/month, 5% annual rate, $5,000 goal
- With no starting balance, the entire balance builds from monthly deposits plus compound interest
- The calculator finds the first month where accumulated deposits plus interest reach $5,000
Frequently Asked Questions
What happens if my goal isn't reachable?
If your current balance, monthly deposit, and interest rate can never reach your goal — most commonly a $0 deposit combined with a 0% interest rate — the calculator tells you directly that the goal isn't reachable with your current inputs, rather than showing a fake time estimate, "0 years," or an error.
Why does "time to reach goal" show months instead of just years?
Rounding a result like 26 months down to "2 years" would hide 2 real months, and rounding up to "3 years" would overstate how long it actually takes. This calculator always shows the exact whole-month result — as months alone under a year, or as years and months together above a year (e.g. "2 years 2 months") — never rounded to the nearest year.
What if I already have enough saved?
If your current balance already meets or exceeds your goal, the calculator reports your goal as already reached, with $0 in additional contributions or growth needed.
Why monthly deposits and monthly compounding specifically?
This calculator is intentionally the simpler, opinionated tool: deposits and compounding are always monthly, matching how most people actually save — a recurring amount set aside from each paycheck. For more control over compounding frequency, see Compound Interest Calculator.
Does this calculator account for taxes on interest earned?
No. This is a savings-growth calculator only — it does not model taxes on interest income, investment fees, or account-specific rules (like a savings account's own rate tiers). It's a planning estimate, not investment or tax advice.