Interest Calculator
Interest is what your money earns, or what you pay to borrow. This works out interest two ways: simple interest, paid on the original amount only, and compound interest, where earned interest is added back and then earns more.
- Free
- Works offline after your first visit
- Saves on this device
- No sign-up
- Updated
How it works
Simple interest is the amount times the rate times the number of years. Compound interest multiplies the amount by one plus the rate divided by the number of periods, raised to the total number of periods.
Choose how often interest is added: yearly, quarterly, monthly or daily. More frequent additions grow the total a little faster. Simple interest ignores this choice.
Worked example
Put $1,000.00 in at 5% for 3 years. With compound interest added monthly, the total is $1,161.47 and the interest earned is $161.47.
Questions
Which should I use, simple or compound?
Simple interest is common for short car loans and some personal loans. Many savings accounts and investments use compound interest, where earlier interest also earns interest.
Does compounding daily make a big difference?
Over short periods, not much. Over many years, the gap between yearly and daily compounding grows, so the frequency matters most for long savings.
Can I use this for a loan?
Yes. The same formulas show what a loan costs in interest, though most loans also have fees and fixed payment schedules.
More like this
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- Credit Card Interest CalculatorMonthly interest and payoff time at a set payment.
- Interest-Only Loan CalculatorPayment during the interest-only years, then after.
- Compound Interest CalculatorSavings growth with interest added over time.
- Mortgage CalculatorFull monthly payment, total interest and payoff date.
- Amortization CalculatorPayment and a month-by-month payoff schedule.