Compound Interest Calculator
See how your money grows over time with compounding. Add regular contributions to project long-term savings goals.
Quick presets
Principal & rate
Duration & contributions
Final balance
$144,572.72
14.46× your principal
Total interest
$86,572.72
1,345.7% total growth
Total contributed
$58,000.00
$200.00/month × 20 yrs
Effective annual rate
7.2290%
Compounding monthly (12×/year)
Growth over time
Year-by-year breakdown
| Year | Opening Balance | Contributions | Interest | Closing Balance |
|---|---|---|---|---|
| 1 | $10,000.00 | $2,400.00 | $801.42 | $13,201.42 |
| 2 | $13,201.42 | $2,400.00 | $1,032.85 | $16,634.27 |
| 3 | $16,634.27 | $2,400.00 | $1,281.01 | $20,315.28 |
| 4 | $20,315.28 | $2,400.00 | $1,547.11 | $24,262.39 |
| 5 | $24,262.39 | $2,400.00 | $1,832.45 | $28,494.83 |
| 6 | $28,494.83 | $2,400.00 | $2,138.41 | $33,033.24 |
| 7 | $33,033.24 | $2,400.00 | $2,466.49 | $37,899.74 |
| 8 | $37,899.74 | $2,400.00 | $2,818.29 | $43,118.03 |
| 9 | $43,118.03 | $2,400.00 | $3,195.52 | $48,713.55 |
| 10 | $48,713.55 | $2,400.00 | $3,600.02 | $54,713.58 |
| 11 | $54,713.58 | $2,400.00 | $4,033.77 | $61,147.34 |
| 12 | $61,147.34 | $2,400.00 | $4,498.86 | $68,046.20 |
| 13 | $68,046.20 | $2,400.00 | $4,997.58 | $75,443.79 |
| 14 | $75,443.79 | $2,400.00 | $5,532.35 | $83,376.14 |
| 15 | $83,376.14 | $2,400.00 | $6,105.79 | $91,881.93 |
| 16 | $91,881.93 | $2,400.00 | $6,720.67 | $101,002.60 |
| 17 | $101,002.60 | $2,400.00 | $7,380.00 | $110,782.60 |
| 18 | $110,782.60 | $2,400.00 | $8,087.00 | $121,269.60 |
| 19 | $121,269.60 | $2,400.00 | $8,845.11 | $132,514.70 |
| 20 | $132,514.70 | $2,400.00 | $9,658.02 | $144,572.72 |
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Help & answers
Frequently Asked Questions
What is compound interest and how is it calculated?
Compound interest grows on both the original principal and the accumulated interest each period, producing faster growth than simple interest over time.
How does compounding frequency affect my return?
More frequent compounding — monthly vs yearly — produces slightly higher returns because interest is added to the principal more often within the same annual rate.
Can I include regular monthly contributions?
Yes. You can add a monthly contribution amount and the calculator will model how regular savings combine with compounding growth over the selected period.
Are projected returns guaranteed?
No. Projections use your entered rate assumption and are for planning purposes only. Actual returns depend on the financial product, fees, and market behavior.
Important disclaimer: Alexonic Tools is completely free to use. There is no charge, and we do not save tool inputs or generated results. We value customer privacy and keep building and fixing each day. Always verify important financial, payroll, legal, tax, business, or production-code results before relying on them. If you see an issue, need a tool, or require an update, send feedback to the developer.