Saving $300 a month at 5% grows to $46,585 in 10 years — $10,585 of it interest.
Putting $300 away every month at 5% interest gets you to $46,585 in 10 years. You will have paid in $36,000 of your own money, so $10,585 of that balance is interest the bank paid you. Keep going for 20 years and the balance reaches $123,310 — interest alone becomes $51,310.
That gap is compounding: interest starts earning interest, so the later years add far more than the early ones. The calculator below is set to $300 a month at 5% — add a starting balance, change the rate to your account’s APY, or switch to goal mode to work out what monthly amount hits a target.
Final Balance (Nominal)
Total Contributions: $70,000
Savings Growth Over Time
Future Value breakdown
Annual Schedule Breakdown
| Year | Total Contributions | Total Interest (Gross) | Nominal Balance |
|---|---|---|---|
| 0 | $10,000 | — | $10,000 |
| 1 | $16,000 | $651 | $16,651 |
| 2 | $22,000 | $1,642 | $23,642 |
| 3 | $28,000 | $2,991 | $30,991 |
| 4 | $34,000 | $4,716 | $38,716 |
| 5 | $40,000 | $6,837 | $46,837 |
| 6 | $46,000 | $9,372 | $55,372 |
| 7 | $52,000 | $12,345 | $64,345 |
| 8 | $58,000 | $15,776 | $73,776 |
| 9 | $64,000 | $19,690 | $83,690 |
| 10 | $70,000 | $24,111 | $94,111 |
At 5% compounded monthly, starting from zero, before tax and inflation.
| Time saving | You paid in | Balance |
|---|---|---|
| 5 years | $18,000 | $20,402 |
| 10 years | $36,000 | $46,585 |
| 15 years | $54,000 | $80,187 |
| 20 years | $72,000 | $123,310 |
| 25 years | $90,000 | $178,653 |
| 30 years | $108,000 | $249,678 |