Your savings, year by year: what you put in, and what interest on interest adds.
Your answer
Enter a starting amount, a rate and the years, and this space shows the final balance, the interest earned and the growth year by year.
The working
r is the yearly rate, n how often interest is added each year, t the years, m the number of monthly deposits, and g the same rate per month: (1 + r ÷ n)n ÷ 12 − 1.
$10,000 × (1 + 0.0650 ÷ 12)12 × 15 = $26,442.01; deposits: $250 × 303.54 = $75,886.19; total $102,328.20.
Good to know
US savings accounts are insured by the FDIC up to its limit; investment returns are not guaranteed. This is not financial advice.
Questions
Balance = start × (1 + r ÷ n)^(n × years), where r is the yearly rate and n is how many times a year interest is added. Monthly deposits are added and grow the same way. $10,000 plus $250 a month for 15 years at 6.5% compounded monthly grows to $102,328.20.
Less than people think. $10,000 at 5% for 10 years becomes $16,288.95 compounded yearly, $16,470.09 monthly and $16,486.65 daily. The rate and the time matter far more.
A lot. $200 a month at 7% grows to $243,994.20 over 30 years, but to $104,185.33 if you start 10 years later. Waiting saves you $24,000 of deposits and costs you about $139,800 at the end.
Divide 72 by the yearly rate for a quick estimate. At 7% the rule of 72 gives about 10.3 years; the exact answer is 10.24 years.
APR is the stated yearly rate. APY is what you actually earn once compounding is included. 6.5% compounded monthly is an APY of 6.70%.
No. It assumes the same rate every year, no fees and no tax. Savings rates change, and investments can fall. Use the Today’s money tab to see the result after inflation.
Printout
One page for the fridge or a meeting with your bank: your plan, the goal, and the balance year by year.
For spreadsheets and code
In a spreadsheet (monthly compounding): =FV(6.50%/12, 180, -250, -10000) gives $102,328.20.
start, monthly, r, n, years = 10000, 250, 0.065, 12, 15
months = years * 12
g = (1 + r / n) ** (n / 12) - 1
balance = start * (1 + r / n) ** (n * years) + (monthly * ((1 + g) ** months - 1) / g if g else monthly * months)
print(round(balance, 2))Both use your current numbers and print the same balance as the calculator.
For: ______________________ Date: 2 November 2026
| Start | $10,000 | Each month | $250 (end of month) |
|---|---|---|---|
| Yearly rate | 6.50% added monthly (APY 6.70%) | Years | 15 (to 2041) |
| Balance | $102,328.20 | Paid in / interest | $55,000 / $47,328 |
| Goal | $100,000: $242.33 a month | In today’s money | $65,680.58 at 3.0% inflation |
| Year | Balance | Paid in | Interest | Year | Balance | Paid in | Interest |
|---|---|---|---|---|---|---|---|
| 2027 | $13,761 | $13,000 | $761 | 2035 | $54,483 | $37,000 | $17,483 |
| 2028 | $17,773 | $16,000 | $1,773 | 2036 | $61,223 | $40,000 | $21,223 |
| 2029 | $22,055 | $19,000 | $3,055 | 2037 | $68,414 | $43,000 | $25,414 |
| 2030 | $26,623 | $22,000 | $4,623 | 2038 | $76,087 | $46,000 | $30,087 |
| 2031 | $31,497 | $25,000 | $6,497 | 2039 | $84,273 | $49,000 | $35,273 |
| 2032 | $36,697 | $28,000 | $8,697 | 2040 | $93,008 | $52,000 | $41,008 |
| 2033 | $42,246 | $31,000 | $11,246 | 2041 | $102,328 | $55,000 | $47,328 |
| 2034 | $48,166 | $34,000 | $14,166 |
Estimate only: same rate every year, no fees or tax, not financial advice. calculationtime.com/calculators/compound-interest-calculator/ · printed 2 November 2026
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