Line chart
Finance
Money Market Calculator
Calculate money market returns with APY, 7-day yield, taxes, target savings, comparisons, and a cash growth chart.
Period
Rate
%
Target amount mode
Ending Balance
$10,450.00
Total Interest
$450.00
Effective APY
4.50%
Investment Summary
Period
365 days
Rate Type
APY
Compare scenarios
Yield chart
Balance growth over time.
Chart values are rounded to cents.
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About this calculator
Method, formulas, and limits.What this does
Calculates the future value of a money market deposit using APY, daily compounding, and 7-day yield. Supports after-tax earnings calculations, target savings mode to find the required principal or rate, and comparison rows for side-by-side scenario analysis with a growth chart.
Who it is for
Savers and investors who want to estimate returns on money market accounts or money market funds. Useful for comparing deposit accounts, planning savings goals, and understanding how compounding frequency affects growth.
How it works
The calculator applies the chosen compounding frequency (daily, monthly, quarterly, annually) to the principal over the selected time period. In target mode it solves for the required principal or rate to reach a goal balance. After-tax results apply the entered tax rate to the gross interest earned to show net earnings.
Limitations
Assumes a constant APY throughout the entire period and does not model rate changes, withdrawal penalties, or tiered interest structures. The 7-day yield is a backward-looking measure and does not guarantee future performance.
Key calculations
- Future Value (Compound Interest)
- The ending balance with compounding is FV = P × (1 + r/n)^(n×t), where P is the principal, r is the annual rate as a decimal, n is the number of compounding periods per year, and t is the time in years.
- Effective APY from Nominal Rate
- APY = (1 + r_nominal/n)^n - 1 converts a nominal rate compounded n times per year into the effective annual percentage yield, reflecting the true return including compounding.
- After-Tax Balance
- The after-tax balance is afterTax = P + (FV - P) × (1 - taxRate), which reduces only the interest earned by the tax rate while leaving the original principal untouched.
- Target Principal
- To find the principal needed to reach a savings goal, the calculator solves P = target / (1 + r/n)^(n×t), working backward from the target balance.
Reference ranges
- High-Yield Money Market APY
- High-yield money market accounts typically offer APYs in the 3-5% range in normal rate environments. Rates move with the federal funds rate and vary by institution.
- Compounding Frequency Impact
- Daily compounding earns roughly 0.01-0.05% more effective APY than monthly compounding at typical rates, with the gap widening at higher rates and longer terms.
- 7-Day Yield Range
- Prime money market fund 7-day yields typically range from 2% to 5.5% depending on the fund's expense ratio, portfolio composition, and prevailing short-term interest rates.
How to use it
- 1.Enter the depositAdd the principal, rate type, rate, and savings period.
- 2.Adjust taxes or target modeOptionally add a tax rate or switch on target amount mode for goal planning.
- 3.Compare the resultReview ending balance, interest, effective APY, after-tax balance, comparison rows, and the chart.
APY (Annual Percentage Yield) reflects the true annual return including the effect of compounding, while APR (Annual Percentage Rate) is a simple yearly rate that does not include compounding. For a given nominal rate, APY will always be equal to or higher than APR. This distinction matters when comparing accounts that compound at different frequencies.
The 7-day yield is the average income return of a money market fund over the past seven days, annualized to show what the fund would earn in a year if that rate held steady. It is the standard SEC-required quote for money market funds and reflects fund expenses. Because it is backward-looking, it does not predict future performance.
The more frequently interest compounds, the faster your balance grows because each compounding period adds interest on top of previously earned interest. Daily compounding produces a slightly higher ending balance than monthly or quarterly compounding at the same nominal rate. Over long periods or large balances this difference becomes meaningful, which is why APY is the better comparison metric.
Yes, switch to target mode and enter your desired ending balance and time horizon. The calculator will solve for the required principal deposit or the interest rate needed to reach your goal. This is useful for planning savings milestones like an emergency fund or a near-term purchase target.
You can optionally enter a tax rate to see estimated after-tax earnings alongside the gross return. The calculator applies the tax rate to the interest earned only, not the principal. This is a simplified estimate that does not account for state-level taxes, AMT, or itemized deductions, so consult a tax professional for your specific situation.
A money market account (MMA) is a bank deposit product that is typically FDIC-insured up to $250,000 and may offer a variable APY. A money market fund is a type of mutual fund that invests in short-term government and corporate debt and is not FDIC-insured, though it aims for a stable $1 NAV. Money market accounts quote APY, while money market funds quote 7-day yield.
Yes, the calculator works for any interest-bearing deposit account. The comparison mode lets you enter multiple rate scenarios side by side, and the chart visualizes growth over time so you can compare ending balances across accounts, terms, or compounding frequencies at a glance.
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