Interest Calculator for United States
Calculate both Simple and Compound interest on your savings or loans.
Region: United States (USD)
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Quick Tip
Enter the APY from your bank for savings, or test a cautious and an optimistic return (for example 4% and 7%) for investments.
About This Tool
Why use Interest Calculator?
US banks advertise savings returns as APY (annual percentage yield), which already includes the effect of compounding. High-yield savings accounts, CDs and money market accounts at FDIC-insured banks are covered up to $250,000 per depositor, per insured bank, for each account ownership category.
For long-term goals, tax-advantaged accounts such as a 401(k), traditional IRA or Roth IRA can matter as much as the rate itself, because growth is tax-deferred or tax-free. Interest earned in a regular savings account is taxed as ordinary income, and investment returns in the stock market are not guaranteed, so model a range of rates rather than a single optimistic one.
Key Benefits
Compounding made visible
See how much of the final balance comes from your own deposits and how much comes from interest earned on interest.
Monthly contribution planning
Model regular deposits the way most Americans save: automatic monthly transfers or payroll contributions to a 401(k).
Scenario comparison
Compare a high-yield savings rate against long-run market returns before deciding where to keep your money.
How to use Interest Calculator
- 1
Enter the APY from your bank for savings, or test a cautious and an optimistic return (for example 4% and 7%) for investments.
- 2
Choose simple or compound interest.
- 3
Enter the principal amount.
- 4
Add the annual interest rate and the time period.
- 5
Compare the interest earned and the final amount.
Best use cases
Check the return on a fixed deposit or certificate of deposit before you lock money in.
See why compound interest overtakes simple interest on longer terms.
Verify the interest on a simple-interest personal or family loan.
Work through simple and compound interest homework with an instant check.
Interest Calculator FAQs
What is the difference between APY and APR on savings?
APR is the simple annual rate, while APY includes compounding within the year. For savings, APY is the figure to compare because it shows what you actually earn over a year.
Is my money insured in a US savings account?
Deposits at FDIC-insured banks are protected up to $250,000 per depositor, per insured bank, for each account ownership category. Credit unions have similar coverage through the NCUA. Investments such as stocks and mutual funds are not deposit-insured.
What return should I assume for long-term investing?
No return is guaranteed. Many people test a conservative figure and a more optimistic one, then plan around the lower result. Remember that inflation reduces the real value of future balances.
Is interest on savings taxable in the US?
Yes. Interest from ordinary savings accounts and CDs is generally taxed as ordinary income in the year it is earned. Growth inside a 401(k) or IRA is tax-deferred, and qualified Roth withdrawals are tax-free.
Which currency does this interest calculator use?
Amounts are shown in US Dollars (USD). The formulas are the same everywhere, so you can switch to another country version if you need a different currency.
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