How long 300 a month takes
Goal $20,000.00. Already saved $2,000.00. Deposit $300.00 a month at 4%.
The balance first reaches the goal after 4 years and 6 months (53.7 months exactly).
Savings goal calculator
Two questions, one formula. How long a monthly deposit takes, or how much a month you need in order to arrive on time.
Symbol only. Amounts are not converted.
%
Time to the goal
4 years and 6 months
53.7 months exactly, then rounded up to the next deposit.
- Balance then
- $20,111.03
- Deposits made
- 54
Next: Compound interest calculatorWatch a deposit grow toward that target.
Same end-of-month, monthly-compounding model as the compound interest calculator.
The numbers, period by period
| Period | You put in | Interest | Balance |
|---|---|---|---|
| Year 1 | $5,600.00 | $148.22 | $5,748.22 |
| Year 2 | $9,200.00 | $449.15 | $9,649.15 |
| Year 3 | $12,800.00 | $909.01 | $13,709.01 |
| Year 4 | $16,400.00 | $1,534.28 | $17,934.28 |
| Month 54 | $18,200.00 | $1,911.03 | $20,111.03 |
How this is calculated
- Step 1
The target
A balance you want, and what you already have.
- Step 2
One question
Either how long a monthly deposit takes, or how much a month a date needs.
- Step 3
Interest
Optional. Zero means the gap is just divided by the months.
Solve the future-value annuity for time, or for the deposit
FV = P(1 + i)^n + PMT × ((1 + i)^n − 1) ÷ i
| FV | The goal. |
|---|---|
| P | What you have already saved. |
| PMT | The end-of-month deposit. This is the unknown in monthly-amount mode. |
| n | Months. This is the unknown in time-to-goal mode. |
| i | Monthly rate: annual rate divided by 12. |
Time mode rearranges the formula and takes a logarithm. The headline is the first month-end at which the balance has reached the goal, which is the exact result rounded up.
Payment mode solves for PMT over a term you choose. If the money you already have grows past the goal by itself, the deposit comes out at zero or below and the tool says you do not need to add more.
This matches the compound interest calculator, not the beginning-of-month SIP calculator. A loan payment in the other direction is the EMI calculator.
Worked examples
Loading an example fills the tool and scrolls you back to the result. Money examples stay in US dollars on the page. The symbol you picked changes; the numbers do not convert.
The deposit that hits 10,000 in 3 years
Reach $10,000.00 in 3 years. You already have $1,500.00. Rate 4% a year.
Save $217.62 at the end of each month.
No interest, just deposits
Goal $5,000.00. Already saved $500.00. Deposit $250.00 a month at 0%.
The balance first reaches the goal after 1 year and 6 months (18.0 months exactly).
Embed this calculator
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<iframe src="/embed/savings-goal" title="Savings goal calculator" width="100%" height="720" style="border:0;max-width:42rem" loading="lazy"></iframe>Questions
What is the difference between the two modes?
Time to the goal asks how many monthly deposits it takes at an amount you can save. Monthly amount asks what to save so you arrive within a term you already chose.
When is the interest added?
Monthly, from a nominal annual rate divided by 12, with deposits at the end of the month. A 0% rate is allowed and turns the problem into plain division.
What if I already have more than the goal?
You have reached it. No rate and no deposit will be invented to fill a gap that is not there.
What if growth alone covers the goal?
Monthly amount mode says you do not need further deposits. It will not tell you to save a negative number.