Simple Interest
Calculates simple interest over a number of periods.
Inputs
The Ultimate Guide to Simple Interest
Welcome to the EasyToolz Simple Interest Calculator. Whether you are loaning money to a friend, buying a short-term certificate of deposit (CD), or studying basic finance, understanding simple interest is the foundation of borrowing and lending.
What is Simple Interest?
Simple interest is a quick method of calculating the interest charge on a loan. Unlike compound interest (where you pay "interest on the interest"), simple interest is determined strictly by multiplying the daily interest rate by the principal by the number of days that elapse between payments. The principal never increases.
How to Use This Calculator
Calculate your costs or returns instantly:
- Principal Amount: The initial amount of money borrowed or invested.
- Annual Interest Rate: The percentage charged or earned per year.
- Time Period: The duration of the loan or investment.
- Calculate: Discover exactly how much total interest will accrue.
The Mathematical Formula
The standard algebraic formula for simple interest is famously known as I = PRT:
- I = Total Interest
- P = Principal amount
- R = Rate of interest per year (in decimal form)
- T = Time period involved (in years)
Frequently Asked Questions
Do banks use simple interest for mortgages?
No. Mortgages and credit cards almost universally use compound interest or an amortized schedule. Simple interest is usually reserved for short-term personal loans, auto loans, and basic savings accounts.