Money Market Fund Calculator: What Your Cash Grows To
Work out what a money market fund grows to from a starting balance plus regular monthly deposits — a low-risk, liquid place to hold cash and earn a yield close to short-term interest rates.
Adjust the inputs and select Calculate for a full breakdown.
Year-by-year growth schedule
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Future value | Total contributions | Total interest earned |
|---|---|---|---|
| $10k + $500/mo · 4% · 5yr | $45,359.46 | $40,000.00 | $5,359.46 |
| $25k + $0/mo · 5% · 3yr (parked cash) | $29,036.81 | $25,000.00 | $4,036.81 |
| $0 + $1,000/mo · 4.5% · 2yr | $25,064.03 | $24,000.00 | $1,064.03 |
| $50k + $0/mo · 4% · 1yr | $52,037.08 | $50,000.00 | $2,037.08 |
How This Calculator Works
Enter your starting balance, monthly deposit, the fund's annual yield, and the years. The calculator compounds the balance monthly and shows the ending value and how much is earnings. Money market funds aim to keep a stable value while paying a yield that tracks short-term rates.
The Formula
Future Value with Regular Contributions
P = starting amount, PMT = monthly contribution, r = monthly rate (annual ÷ 12), n = number of months
Worked Example
A $10,000 starting balance plus $500 a month for 5 years at 4% grows to about $45,359 — with roughly $5,359 of that being earnings. Money market funds are a low-risk place to park cash — they invest in very short-term, high-quality debt and aim to maintain a stable share price — paying a yield that closely tracks short-term interest rates. They're popular for emergency funds, the cash portion of a portfolio, and money awaiting investment, offering more yield than a checking account with high liquidity.
Key Insight
Money market funds sit between a savings account and bond investments, and understanding what they are (and aren't) matters. They're mutual funds that invest in very short-term, high-quality debt (Treasury bills, commercial paper, repos) and aim to maintain a stable $1.00 share price, paying a yield that tracks short-term rates — so the yield is variable and this projection is an estimate, not a guarantee (it can rise or fall as rates move). Important distinctions: a money market fund is an investment product (offered by brokerages/fund companies) and is not the same as a money market deposit account at a bank — the bank account is FDIC-insured, while a money market fund is not FDIC-insured (though it's considered very low-risk, money market funds can in rare crises 'break the buck' or impose redemption gates, so it's not risk-free like an insured deposit). For most savers the practical role is the same as high-yield savings: a liquid, low-risk home for cash earning a competitive yield. A few notes: the income is taxable (some funds hold government or municipal securities for tax advantages — government money market funds and tax-exempt funds exist), fund expense ratios reduce the net yield (favor low-cost funds), and the yield, while solid, typically trails long-term investment returns — so it's for safety and liquidity, not long-term growth. Use it for emergency funds, near-term goals, and idle cash, and invest money with a long horizon elsewhere.
Frequently Asked Questions
How is money market fund growth calculated?
The starting balance and each monthly deposit compound at the fund's yield (annual yield ÷ 12 per month). $10,000 plus $500/month for 5 years at 4% grows to about $45,359, with roughly $5,359 of that being earnings.
Is a money market fund the same as a money market account?
No. A money market fund is an investment product from a brokerage/fund company and is not FDIC-insured. A money market deposit account is a bank account that is FDIC-insured. Both are low-risk and liquid, but the insurance status differs — an important distinction for risk-averse savers.
Is the yield guaranteed?
No — money market yields are variable and track short-term interest rates, so the yield can rise or fall over time. This projection assumes a constant yield, so treat it as an estimate. Check the fund's current 7-day yield, which is the standard measure of what it's paying now.
Are money market funds safe?
They're considered very low-risk — investing in very short-term, high-quality debt and aiming for a stable share price — but not risk-free like an FDIC-insured deposit. In rare market crises, funds can 'break the buck' (drop below $1.00) or impose redemption restrictions. For most savers they're a safe place for cash, just not insured.
What is a money market fund best used for?
A liquid, low-risk home for cash — emergency funds, near-term goals, and money awaiting investment — earning a competitive short-term yield. It's not for long-term growth, since the yield typically trails long-term investment returns. Watch the expense ratio (it reduces net yield) and remember the income is taxable.
Related Calculators
Data Sources & Benchmarks
This calculator draws on 1 independent, dated source. The starting values for annual yield are taken from the benchmarks below and refresh whenever the snapshots are updated.
Methodology & Review
The future value compounds a starting balance and a fixed monthly deposit at the annual yield, compounded monthly. It assumes deposits at month end and a constant yield; it ignores fund fees, taxes on income, and yield changes (money market yields are variable).
Written by Ugo Candido · Last updated May 22, 2026.