Money Market Savings Account Calculator
Project a money market savings balance — starting principal, APY, optional monthly deposits, and years. Click any i for detail.
Savings inputs
Starting balance ($)
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Starting balance
Current money market or savings balance. |
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APY (%)
i
APY
Annual percentage yield advertised by the account (already includes compounding frequency in the APY). |
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Monthly contribution ($)
i
Monthly contribution
Amount you add each month. Use 0 for a static balance. |
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Years
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Years
How long you leave the money growing at this APY assumption. |
How to use this calculator
- Enter starting balance and APY.
- Add a monthly contribution if you save regularly.
- Set the number of years.
- Read projected balance and interest earned.
Results explained
The headline is the projected balance after monthly compounding equivalent to the APY, plus deposits. Interest earned is balance minus what you put in.
Quick reference: money market growth
APY already reflects compounding; we convert to a monthly equivalent rate.
| Item | Detail |
|---|---|
| Monthly rate | (1 + APY)^(1/12) − 1 |
| Each month | Balance × (1 + r) + deposit |
| Interest earned | Future − principal − deposits |
Need cash from a retirement account instead? See the 401k early withdrawal calculator.
How the estimate is built
Convert APY to a monthly growth factor, then iterate months: balance grows, then the contribution is added.
Example scenario
$10,000 at 4.25% APY with $250/month for 5 years grows by both deposits and compounding — interest is the gap above total contributions.
FAQ
APY vs interest rate?
APY includes compounding. Using APY here avoids double-counting compound frequency.
Variable rates?
Money market APYs change. Re-run when the bank updates yield.
Taxes on interest?
Interest is usually taxable; this projection is pre-tax.