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Interest Calculator

This Compound Interest Calculator can help determine the compound interest accumulation and final balances on both fixed principal amounts and additional periodic contributions. There are also optional factors available for consideration, such as the tax on interest income and inflation.

Modify the values and click the Calculate button to use
Contribute at the
of each compounding period
Investment length
years months

Results

Ending balance $54,535.20
Total principal $45,000.00
Total contributions $25,000.00
Total interest $9,535.20
Interest of initial investment $5,525.63
Interest of the contributions $4,009.56
Buying power of the end balance after inflation adjustment $47,042.54
Initial investment: $20,000.00 (37%) Contributions: $25,000.00 (46%) Interest: $9,535.20 (17%) 37%46%17% Initial investment Contributions Interest

Accumulation Schedule

Year Deposit Interest Ending balance
1 $25,000.00 $1,250.00 $26,250.00
2 $5,000.00 $1,562.50 $32,812.50
3 $5,000.00 $1,890.63 $39,703.13
4 $5,000.00 $2,235.16 $46,938.28
5 $5,000.00 $2,596.91 $54,535.20
$0 $12K $24K $36K $48K $60K Year 1: Ending Balance: $26,250.00 Initial: $20,000.00 Contributions: $5,000.00 Interest: $1,250.00 Year 2: Ending Balance: $32,812.50 Initial: $20,000.00 Contributions: $10,000.00 Interest: $2,812.50 Year 3: Ending Balance: $39,703.13 Initial: $20,000.00 Contributions: $15,000.00 Interest: $4,703.13 Year 4: Ending Balance: $46,938.28 Initial: $20,000.00 Contributions: $20,000.00 Interest: $6,938.28 Year 5: Ending Balance: $54,535.20 Initial: $20,000.00 Contributions: $25,000.00 Interest: $9,535.20 1 2 3 4 5 Year
Initial investment Contributions Interest

Understanding your calculation

Method, example and limitations

How the calculation works

Simple interest grows only the principal; compound interest also grows previously earned interest. Check the selected mode, rate period and contribution settings before comparing balances.

Example to check

At 5% simple annual interest, $1,000 earns $50 per year and reaches $1,100 after two years. Annual compounding instead produces $1,102.50 over the same period.

Before using the result

Do not enter a monthly rate in an annual-rate field. Results depend on payment timing and assume the selected rate continues; lender fees and taxes may be excluded.

Calculation methodology · Report a result that needs review