Calculate compound interest, simple interest, savings goals, final balances, interest earned, inflation-adjusted value, and monthly savings needed.
Free Calculator
Estimate compound interest, simple interest, and monthly savings needed to reach a target goal.
| Year | Contributions | Interest | Balance | Real Value |
|---|---|---|---|---|
| 1 | $2,400 | $723 | $13,123 | $12,741 |
| 2 | $2,400 | $949 | $16,472 | $15,526 |
| 3 | $2,400 | $1,191 | $20,062 | $18,360 |
| 4 | $2,400 | $1,450 | $23,913 | $21,246 |
| 5 | $2,400 | $1,729 | $28,041 | $24,189 |
| 6 | $2,400 | $2,027 | $32,468 | $27,192 |
| 7 | $2,400 | $2,347 | $37,215 | $30,260 |
| 8 | $2,400 | $2,690 | $42,306 | $33,397 |
| 9 | $2,400 | $3,058 | $47,764 | $36,607 |
| 10 | $2,400 | $3,453 | $53,617 | $39,896 |
| 11 | $2,400 | $3,876 | $59,893 | $43,268 |
| 12 | $2,400 | $4,330 | $66,623 | $46,728 |
| 13 | $2,400 | $4,816 | $73,839 | $50,281 |
| 14 | $2,400 | $5,338 | $81,577 | $53,932 |
| 15 | $2,400 | $5,897 | $89,874 | $57,687 |
| 16 | $2,400 | $6,497 | $98,771 | $61,551 |
| 17 | $2,400 | $7,140 | $108,311 | $65,530 |
| 18 | $2,400 | $7,830 | $118,541 | $69,630 |
| 19 | $2,400 | $8,569 | $129,510 | $73,858 |
| 20 | $2,400 | $9,362 | $141,272 | $78,219 |
Formula
Compound interest applies interest repeatedly over time, while simple interest applies interest only to the original principal.
Planning
Interest calculations help compare savings plans, investment assumptions, loan cost, contribution timing, inflation impact, and long-term growth scenarios.
Use cases
Use it to estimate savings growth, simple interest, compounding impact, and monthly savings needed to reach a future goal.
Use the result as a planning estimate, then verify important investment, tax, or loan decisions with a qualified professional.
Use the result as a planning estimate, then verify important investment, tax, or loan decisions with a qualified professional.
Use the result as a planning estimate, then verify important investment, tax, or loan decisions with a qualified professional.
Use the result as a planning estimate, then verify important investment, tax, or loan decisions with a qualified professional.
Use the result as a planning estimate, then verify important investment, tax, or loan decisions with a qualified professional.
Use the result as a planning estimate, then verify important investment, tax, or loan decisions with a qualified professional.
Calculator details
Last updated: July 2026
Formula used
Simple interest = principal × rate × time. Compound interest = principal × (1 + rate / n)^(n × time).
Assumptions
Example calculation
$1,000 at 5% simple interest for one year earns $50.
When to use this calculator
Use it to estimate interest earned or owed before comparing savings, loans, or invoices.
Disclaimer
This calculator is for estimation and educational use only. It does not replace professional financial, tax, legal, mortgage, investment, or accounting advice.
Questions
It estimates compound interest, simple interest, final balance, total interest earned, inflation-adjusted value, effective annual rate, and the monthly savings needed to reach a target goal.
Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus previously earned interest, so growth can accelerate over time.
More frequent compounding can slightly increase the final balance because interest is added more often. The impact is usually larger over longer time periods or at higher interest rates.
No. It is for educational planning only. Actual returns, interest costs, taxes, fees, inflation, and account rules can vary. Review important savings, investment, or loan decisions with a qualified professional.
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