Compound Interest Calculator
See how savings grow with compound interest and regular contributions. Pick your rate, frequency and term, then watch contributions vs. interest stack up.
Calculator
Compounding is building
29%You've put in $13,000.00, and it's already earned $5,207.33 in interest — 29% of your $18,207.33 balance. Compounding speeds up the longer you stay invested.
Starting + contributions: $13,000.00 · Interest: $5,207.33
Show data table
| How your balance grows | Starting + contributions | Interest |
|---|---|---|
| Y1 | $1,100.00 | $5.00 |
| Y1 | $1,300.00 | $16.58 |
| Y1 | $1,500.00 | $30.28 |
| Y1 | $1,700.00 | $46.12 |
| Y1 | $1,900.00 | $64.12 |
| Y1 | $2,100.00 | $84.31 |
| Y2 | $2,300.00 | $106.71 |
| Y2 | $2,500.00 | $131.34 |
| Y2 | $2,700.00 | $158.22 |
| Y2 | $2,900.00 | $187.37 |
| Y2 | $3,100.00 | $218.82 |
| Y2 | $3,300.00 | $252.59 |
| Y3 | $3,500.00 | $288.71 |
| Y3 | $3,700.00 | $327.19 |
| Y3 | $3,900.00 | $368.06 |
| Y3 | $4,100.00 | $411.35 |
| Y3 | $4,300.00 | $457.08 |
| Y3 | $4,500.00 | $505.26 |
| Y4 | $4,700.00 | $555.94 |
| Y4 | $4,900.00 | $609.13 |
| Y4 | $5,100.00 | $664.86 |
| Y4 | $5,300.00 | $723.16 |
| Y4 | $5,500.00 | $784.04 |
| Y4 | $5,700.00 | $847.53 |
| Y5 | $5,900.00 | $913.67 |
| Y5 | $6,100.00 | $982.48 |
| Y5 | $6,300.00 | $1,053.98 |
| Y5 | $6,500.00 | $1,128.21 |
| Y5 | $6,700.00 | $1,205.18 |
| Y5 | $6,900.00 | $1,284.93 |
| Y6 | $7,100.00 | $1,367.48 |
| Y6 | $7,300.00 | $1,452.87 |
| Y6 | $7,500.00 | $1,541.12 |
| Y6 | $7,700.00 | $1,632.25 |
| Y6 | $7,900.00 | $1,726.31 |
| Y6 | $8,100.00 | $1,823.31 |
| Y7 | $8,300.00 | $1,923.29 |
| Y7 | $8,500.00 | $2,026.28 |
| Y7 | $8,700.00 | $2,132.31 |
| Y7 | $8,900.00 | $2,241.40 |
| Y7 | $9,100.00 | $2,353.60 |
| Y7 | $9,300.00 | $2,468.92 |
| Y8 | $9,500.00 | $2,587.40 |
| Y8 | $9,700.00 | $2,709.08 |
| Y8 | $9,900.00 | $2,833.98 |
| Y8 | $10,100.00 | $2,962.14 |
| Y8 | $10,300.00 | $3,093.58 |
| Y8 | $10,500.00 | $3,228.36 |
| Y9 | $10,700.00 | $3,366.48 |
| Y9 | $10,900.00 | $3,508.00 |
| Y9 | $11,100.00 | $3,652.94 |
| Y9 | $11,300.00 | $3,801.34 |
| Y9 | $11,500.00 | $3,953.23 |
| Y9 | $11,700.00 | $4,108.65 |
| Y10 | $11,900.00 | $4,267.63 |
| Y10 | $12,100.00 | $4,430.21 |
| Y10 | $12,300.00 | $4,596.42 |
| Y10 | $12,500.00 | $4,766.31 |
| Y10 | $12,700.00 | $4,939.91 |
| Y10 | $12,900.00 | $5,117.25 |
| Y10 | $13,000.00 | $5,207.33 |
About this calculator
This calculator shows how a lump sum grows over time when interest compounds and you add regular contributions. Use it to project long-term savings, compare how often interest is applied, or estimate what an investment could be worth at a future date.
How to read your results
The headline figure is your projected ending balance. The stacked-area chart separates the money you put in (contributions) from the interest it earned, so you can see how compounding accelerates growth in the later years. The data table beneath the chart lists the balance at the end of each year.
How it's calculated
The future value uses the standard compound-interest formula A = P(1 + r/n)^(nt) combined with the future value of a recurring contribution. P is the starting principal, r the annual rate, n the number of compounding periods per year, and t the number of years. Contributions are applied at the start or end of each period depending on your selection.
Worked example
Start with 1,000, add 100 per month at a 6% annual rate compounded monthly for 10 years.
You contribute 13,000 in total, but the balance grows to roughly 18,200 — about 5,200 of that is compound interest the contributions earned.
Frequently asked questions
What is compound interest?
Compound interest is interest calculated on both your original principal and the interest already added to it. Because each period’s interest goes on to earn interest itself, balances grow faster the longer the money stays invested.
How does the compounding frequency change the result?
More frequent compounding (monthly or daily rather than annually) produces a slightly higher balance, because interest is added — and starts earning — sooner. The gap widens with higher rates and longer terms.
Does this account for taxes or inflation?
No. The projection is before taxes and inflation, so your real spending power will be lower than the nominal balance shown. Treat the figure as a gross estimate rather than a guarantee.
Popular scenarios
Sources
- www.investor.gov/financial-tools-calculators/calculators/compound-interest-calculator
- www.investopedia.com/terms/c/compoundinterest.asp
- www.nerdwallet.com/calculator/compound-interest-calculator
Reviewed by the YouCalc Team · Last reviewed
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