How the Money Market Account Interest Calculator Works
A money market account (MMA) pays interest daily on whatever balance you're holding, which makes it a popular home for emergency funds and short-term cash. Enter your balance and the account's APY (annual percentage yield) to see exactly how much interest builds up per day and over any stretch of time you choose.
The math is simple: daily interest equals your balance times the APY, divided by 365. Multiply that by the number of days you're holding the money to get your pre-tax total. Keep in mind that most banks compound interest daily internally and only credit it to your account monthly, so the timing of when it actually posts can differ from this estimate even though the total amount earned is the same.
Unlike some countries with a flat withholding rate on interest income, U.S. interest is taxed as ordinary income at your marginal federal tax rate (plus state tax where applicable) — there's no separate, lower "interest income tax." Enter your estimated marginal rate to see a rough after-tax figure, which is useful when comparing an MMA against a CD or high-yield savings account.
Frequently Asked Questions
Interest accrues daily based on your balance and the account's APY (annual percentage yield). Daily interest equals balance times APY divided by 365, though many banks compound daily and credit interest monthly, so your actual payout timing may differ.
Yes. Interest from a money market account is taxed as ordinary income at your federal (and possibly state) marginal tax rate — there's no special reduced rate. This calculator applies a tax rate you enter to estimate after-tax interest.
Money market accounts offer easy access to your cash with a variable rate that can rise or fall, while CDs lock in a fixed rate for a set term, often slightly higher. Use MMAs for funds you might need soon and CDs for money you can set aside.