How this calculator works
A money market account is a bank savings account that usually pays more than regular savings and may come with checks or a debit card. Enter the opening balance, what you'll add each month and the account's APY. The calculator compounds monthly at the rate that matches the APY and shows the balance, the interest, and how the same money would do at higher rates.
- Monthly rate i = (1 + APY ÷ 100)^(1/12) − 1, so 12 months of compounding equals the APY exactly.
- Balance after n months = opening balance × (1 + i)ⁿ + monthly deposit × ((1 + i)ⁿ − 1) ÷ i.
- Interest earned = balance − (opening balance + monthly deposit × n).
Worked example
With these inputs: opening balance $10,000; monthly deposit $200; apy 0.63%; years 5.
The result is balance after 5 years $22,506.20, with interest earned $506.20 and total deposited $22,000.00. Money market accounts often pay tiered rates (more on higher balances) and the rate can change at any time, unlike a CD. A money market account at a bank is FDIC-insured; a money market mutual fund is an investment and is not.
Money market account vs savings vs CD
A money market deposit account is a bank savings account, often with a higher rate, a higher minimum balance and some check-writing or debit access. The FDIC's September 2026 national averages were 0.37% for savings, 0.63% for money market accounts and 1.73% for a 12-month CD. A CD pays a fixed rate but locks the money up; a money market rate can change at any time. To split savings across CDs that mature one after another, use the CD ladder calculator.
Money market deposit accounts at an FDIC-insured bank are covered up to $250,000 per depositor, per bank, per ownership category. A money market mutual fund at a brokerage is an investment, not a deposit, and is not FDIC-insured.
Where a money market account fits
Easy access plus interest makes a money market account a good home for an emergency fund or the money you set aside for irregular bills in a sinking fund. In the default example the first year earns $69.92 at the national average; at 4.00% it earns $443.69.
If the account quotes an interest rate rather than an APY, convert it with the APY calculator first. Add the monthly transfer to your bill tracker so it happens on payday like any other bill.
Sources
Frequently asked questions
How much interest does a money market account earn?
Balance × APY a year, plus interest on interest. At the FDIC national average of 0.63% (September 2026), $10,000 earns about $63.00 in a year; at 4.00% APY, $400.00.
What is the average money market rate?
0.63% APY, the FDIC national average for money market accounts published September 21, 2026. Many banks pay more, so compare offers.
How is money market interest calculated?
Most accounts compound daily or monthly and quote the result as an APY. This calculator compounds monthly at (1 + APY)^(1/12) − 1, so a year's growth matches the quoted APY.
Are money market accounts FDIC insured?
Money market deposit accounts at an FDIC-insured bank are, up to $250,000 per depositor, per bank, per ownership category. Money market mutual funds are not.
Is a money market account better than a savings account?
Often it pays more: the FDIC national averages were 0.63% for money market and 0.37% for savings in September 2026. Check the minimum balance and fees, which can cancel out the higher rate.