interest Calculator

Free Online interest Calculator

Compound Interest · Simple Interest · Savings Goal Planner

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Interest Calculator

Compound Interest · Simple Interest · Savings Goal Planner

Compound interest earns interest on both your principal and previously earned interest. It's the most powerful force in investing — the more frequently it compounds and the longer it grows, the more dramatic the effect.

Investment Details

Initial Principal

Annual Interest Rate

Investment Period

yrs

Compounding Frequency

Regular Contribution

Contribution Frequency

Inflation Rate (for real return)

Annual Tax on Interest (taxable account)

% (0 = tax-deferred)

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Growth Summary

—

Final Balance

—

Total Interest Earned

—

📊 Principal vs Interest Composition —

Principal + Contributions

Compound Interest

Initial Principal

—

Total Contributions

—

Interest Earned

—

Growth Multiplier

—

Real Return (inflation-adj.)

—

Effective Annual Rate (EAR)

—

Rule of 72 (doubling)

—

After-Tax Balance

—

🔮 What-If Scenarios

If you invest for 5 more years:—

If rate drops 2% (bear market):—

If rate rises 2% (bull market):—

If contribution doubles:—

Daily vs annual compounding difference:—

📋 Year-by-Year Growth Table

Year	Contributions	Interest Earned	Balance	Real Value

Compound Interest Insights

Simple interest is calculated only on the original principal — not on accumulated interest. Common for short-term loans, bonds, and certificates of deposit. Formula: I = P × r × t.

Loan / Deposit Details

Principal Amount

Annual Interest Rate

Time Unit

Time Period

yrs

Calculation Mode

💵

Simple Interest Summary

—

Total Amount

—

Total Interest

—

Principal

—

Interest Amount

—

Time Period

—

Daily Interest

—

Monthly Interest

—

Annual Interest

—

Total / Principal Ratio

—

Compound Equivalent Rate

—

💰 Principal vs Interest Breakdown

🔮 Comparison Scenarios

If compounded monthly instead (same rate):—

If rate was 2% higher:—

If time period doubled:—

Monthly payment to clear principal + interest:—

Daily cost / daily gain of this interest:—

Simple Interest Insights

Work backwards from your savings target — find out exactly how much you need to save per month, or how long it will take to reach your goal with compound interest working for you.

Your Goal

Target Amount

Current Savings (starting balance)

Annual Interest Rate

Monthly Contribution

Or: Target Timeline

yrs

Inflation Adjustment

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Goal Assessment

—

Monthly Savings Needed

—

Time to Reach Goal (at current rate)

—

🎯 Goal Progress Projection —

Now — Goal: —

—

Target Amount

—

Starting Balance

—

Still Needed

—

Interest Will Cover

—

Balance at Target Year

—

Inflation-Adjusted Target

—

Total You'll Contribute

—

Interest Working for You

—

🔮 Goal Scenarios

If you save $100/month more:—

If rate drops to 4%:—

If you start 2 years later:—

Cost of waiting 5 years to start:—

Inflation-adjusted monthly savings needed:—

📋 Year-by-Year Savings Projection

Year	Contributions	Interest	Balance	vs Goal

Savings Goal Insights

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