Interest Calculator

Calculate compound or simple interest for investments and loans with our free online calculator.

Calculator Type

Calculate Interest

Understanding Interest Calculations

The ToolMasteryHub Interest Calculator is a powerful financial tool that helps you understand how your money grows over time with different interest rates and compounding frequencies. Whether you're planning investments, loans, or retirement savings, our calculator provides accurate projections for your financial decisions.

Compound vs. Simple Interest

Compound Interest

Compound interest is calculated on the initial principal and also on the accumulated interest from previous periods. It's essentially "interest on interest" and is the reason why investments grow exponentially over time.

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

Simple Interest

Simple interest is calculated only on the initial principal amount. The interest payment remains the same throughout the loan term, regardless of how much of the principal has been paid off.

Formula: A = P(1 + rt)

Key Features of Our Calculator

  • Multiple Compounding Periods - Calculate interest with various compounding frequencies from daily to annually
  • Regular Contribution Options - See how additional periodic deposits affect your investment growth
  • Flexible Time Units - Work with years, months, or days for precise calculations
  • Effective Annual Rate - Compare different offers with standardized effective rates
  • Clear Results - Get detailed breakdowns of principal, interest, and total amounts

Common Uses for Interest Calculations

  • Planning retirement savings and projecting account growth
  • Comparing different investment options and rates
  • Understanding the true cost of loans and credit cards
  • Evaluating the impact of additional contributions to investments
  • Determining how long it will take to reach financial goals
  • Analyzing the effect of different compounding frequencies
  • Calculating returns on CDs, bonds, and savings accounts

Use our free Interest Calculator to make informed financial decisions and see how your money can grow over time with the power of compound interest!