Interest Calculator

Calculate simple interest, compound interest, loan payments, and APR with comprehensive analysis. Compare different interest types and understand the true cost of borrowing.

Choose Calculator Type

📊

Simple Interest

Linear interest calculation

📈

Compound Interest

Interest on interest

🏠

Loan Interest

Monthly payments & total cost

💳

APR Calculator

True cost of credit

Interest Earned

Total Amount

Effective Rate

Monthly Payment

Simple Interest Formula

I = P × r × t

Interest = Principal × Rate × Time

Simple Interest Calculator

Calculate simple interest on your principal amount over time.

Principal Amount

Initial amount invested or borrowed

Annual Interest Rate

Time Period

years

Interest Analysis

Principal Amount: $10,000

Interest Earned/Paid: $2,500

Total Amount: $12,500

Effective Rate: 5.00%

Principal vs Interest

Principal 80.0%

Interest 20.0%

Daily Interest: $1.37

Interest Type Comparison

Compare simple vs compound interest and see the difference over time.

Simple vs Compound Interest

Growth comparison over 5 years

Interest Type	Formula	Interest Earned	Total Amount	Difference
Simple Interest	I = P × r × t	$2,500	$12,500	Base
Compound Interest	A = P(1+r/n)^(nt)	$2,763	$12,763	+$263

Conservative (3%)

Simple Interest: $1,500

Compound Interest: $1,593

Advantage: $93

Moderate (7%)

Simple Interest: $3,500

Compound Interest: $4,026

Advantage: $526

Aggressive (12%)

Simple Interest: $6,000

Compound Interest: $7,623

Advantage: $1,623

Payment Schedule & Timeline

Detailed breakdown of payments and interest over time.

Interest Accumulation Timeline

Year-by-year interest growth

Detailed Schedule

Year	Beginning Balance	Interest	Ending Balance	Cumulative Interest

First Year

Interest: $500

Balance: $10,500

Final Year

Interest: $500

Balance: $12,500

Average Annual

Interest: $500

Growth Rate: 5.00%

Interest Guide

Types of Interest

Simple Interest: Calculated only on principal

Compound Interest: Interest on interest

APR: Includes fees and costs

Effective Rate: True annual rate

Interest Formulas

Simple: I = P × r × t

Compound: A = P(1+r/n)^(nt)

Effective: r_eff = (1+r/n)^n - 1

APR: Includes all costs

Key Concepts

• Higher frequency = higher effective rate
• APR shows true cost of borrowing
• Compound interest grows exponentially
• Time significantly impacts returns

Investment Tips

• Compare effective rates, not nominal
• Consider all fees in APR calculations
• Compound frequency matters for returns
• Start early to maximize compounding

Typical Interest Rates

Savings Account: 0.5% - 2%

CDs: 1% - 5%

Mortgages: 3% - 8%

Credit Cards: 15% - 25%

Personal Loans: 6% - 15%

Stock Market: 7% - 10%

Quick Reference

P = Principal amount

r = Annual interest rate

t = Time in years

n = Compounding frequency

I = Interest earned

A = Final amount

Important Notes

• Always compare APR, not just interest rates
• Read all terms and conditions
• Consider tax implications
• Understand penalty fees
• Shop around for best rates