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finance calculator
Calculate simple interest, final amount, and total repayment.
Save this page to compare simple interest rates against compound rate returns, or plan short-term personal notes.
Interest earned
$1,800.00
Summary
Interest earned
$1,800.00
Total interest accumulated.
Total value
$11,800.00
Principal plus interest.
Principal
$10,000.00
Starting deposit amount.
Total return
18.0%
Simple return percentage.
D3 visualization
Analyze how interest returns compare alongside your initial principal investment.
D3 visualization
Watch your interest accumulate over time in a steady linear projection.
Guide
Simple interest is calculated only on the initial principal amount of a loan or investment. Unlike compound interest, which adds previous interest back to the principal, simple interest remains constant across every period.
This tool is useful for short-term loans, personal lending, basic debt notes, or checking introductory financial products.
Compound interest grows exponentially because you earn interest on interest. Simple interest grows linearly. For long-term goals, compounding is highly recommended, but simple interest remains standard for certain bonds and short-term debt agreements.
Principal
The original sum of money lent or invested on which interest is calculated.
Compound interest
Interest calculated on the initial principal and also on the accumulated interest of previous periods.
Interest = Principal x Rate x Time (in years). The total amount is Principal + Interest.
Simple interest is commonly used in short-term personal loans, car loans, certificates of deposit (CDs) with periodic payouts, and treasury bills.
Formula
Interest = Principal × Rate × TimeRate is annual percentage converted into decimal form.
Step by step
Related guides
Guide
Compare simple and compound interest calculations. Understand how compounding frequency affects growth and when each interest model applies to loans and investments.
Guide
Learn how compound interest works, the formula behind exponential growth, and how starting early, regular contributions, and reinvesting dividends accelerate wealth building.