Money Market Income Estimate CalculatorFree online financial calculator — instant results, no sign-up
Estimate income assuming a quoted annual simple yield remains constant for the holding period.
Estimates only, based on the inputs and assumptions shown. This is not financial, investment, tax, or legal advice. Prices, rates and local rules may change; crypto scenarios do not predict returns. Confirm important decisions with a qualified professional.
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About the Money Market Income Estimate Calculator
The Money Market Income Estimate Calculator estimates earnings on a money market balance using a quoted annual simple yield and a holding period in days. It assumes the balance and yield remain constant and prorates annual income using a 365-day year. It shows both estimated income and the starting balance plus that income.
- Balance ($)
- The starting amount held in the money market investment, in dollars, with a default of $20,000.
- Annual simple yield (%)
- The annual rate used to estimate income without compounding, expressed as a percentage, with a default of 4.2%.
- Holding period (days)
- The length of time the balance is held at the assumed yield, measured in days, with a default of 90 days.
Formula and method
I = B × (y / 100) × (d / 365); T = B + I. With the default inputs: I = 20000 × (4.2 / 100) × (90 / 365) ≈ $207.12; T ≈ $20,207.12.
- BStarting balance in dollars.
- yAnnual simple yield entered as a percentage; dividing by 100 converts it to a decimal rate.
- dHolding period in days.
- IEstimated income in dollars over the holding period.
- TStarting balance plus estimated income, in dollars.
Convert the annual simple yield from a percentage to a decimal, multiply it by the balance, and prorate the resulting annual income by the holding period divided by 365. Add the estimated income to the starting balance to obtain the combined total. Retain precision during calculation and display dollar outputs rounded to the nearest cent.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Balance20000 $
- Annual simple yield4.2 %
- Holding period90 days
Results
- Estimated income$207.12
- Balance plus estimated income$20,207.12
How to use the Money Market Income Estimate Calculator
- 1Enter the balance you plan to hold, or keep the default of $20,000.
- 2Enter the annual simple yield, or keep 4.2%; check that the quoted rate is not an APY that includes compounding.
- 3Enter the holding period in days, or keep the default of 90 days.
- 4Run the calculation to estimate income under the constant-balance, constant-yield assumptions.
- 5Review both output rows: the default inputs produce $207.12 in estimated income and $20,207.12 in balance plus estimated income.
Reading your result
“Estimated income” is the modeled earnings for the entered holding period, not a full year's earnings unless the period is 365 days. For the default inputs, this is $207.12. “Balance plus estimated income” adds those earnings to the starting $20,000 balance, producing $20,207.12; it is a combined value estimate, not a guarantee of the account's ending balance.
Limitations
This estimate assumes a constant balance and annual simple yield, uses a fixed 365-day denominator, and excludes compounding. Actual money market yields can change, and products may use different accrual conventions or distribution schedules. Deposits, withdrawals, taxes, fees, and changes in investment value are not modeled separately. An APY or a money market fund's quoted seven-day yield may not be directly equivalent to the annual simple yield required here. The result is an income estimate, not a promised return or an assessment of principal safety.
Common questions
Why does $20,000 at 4.2% for 90 days produce $207.12?+
The calculator multiplies $20,000 by 0.042 and then by 90/365. This prorates the annual simple income to the 90-day holding period and rounds the result to $207.12.
Can I enter my money market account's APY as the annual simple yield?+
Not if you want a like-for-like estimate: APY includes compounding, while this calculator applies simple interest. Use a comparable annual rate excluding compounding when available; entering APY directly treats it as a simple rate.
What if the money market yield changes during my holding period?+
A single calculation will not capture that change. For a simple-income approximation, calculate each interval with its applicable yield and balance, then add the interval income estimates.
Does the $20,207.12 total assume income is reinvested?+
No. It adds the $207.12 estimated income to the starting $20,000 without calculating earnings on that income. If distributions are paid elsewhere, the total represents the starting balance plus those estimated distributions rather than necessarily the balance shown in the account.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.