Money Market Account Calculator
Results are estimates based on the values you enter. Recheck your inputs and assumptions before using the output for decisions.
Project money market account growth from opening deposit, APY, monthly deposit, and years.
Money Market Account Calculator
Free online money market account calculator to estimate account growth from an opening deposit, APY, monthly deposits, and time in years. This calculator is useful for savers, emergency-fund planners, finance students, conservative investors, and anyone comparing cash-management options. Money market accounts are often used when people want a balance between liquidity and interest earnings. They are not the same as long-term investments, but they can still grow meaningfully over time when interest compounds and regular deposits are added.
This calculator uses four main inputs. Opening deposit means the initial amount placed into the money market account. APY means the annual percentage yield offered by the account. Monthly deposit means the amount added every month. Years means how long the account remains funded and earning interest. Once those values are entered, the calculator shows future account value, total deposits, interest earned, and effective monthly rate. These outputs help you see both the ending balance and how much of that total comes from your own deposits versus interest growth.
The formula of money market account growth
Effective monthly rate = (1 + APY)^(1 / 12) – 1
Future value of opening deposit = Opening deposit x (1 + Monthly rate)^Number of months
Future value of monthly deposits = Monthly deposit x [((1 + Monthly rate)^Number of months – 1) / Monthly rate]
Future account value = Future value of opening deposit + Future value of monthly deposits
Total deposits = Opening deposit + (Monthly deposit x Number of months)
Interest earned = Future account value – Total deposits
Here APY means annual percentage yield, effective monthly rate means the monthly growth rate implied by that APY, opening deposit means the initial balance, monthly deposits means the recurring additions to the account, future account value means the projected ending balance, total deposits means the total amount you personally put in, and interest earned means the extra amount created by the account yield.
Solved Example
Example 1: Find the future value if the opening deposit is $10,000, APY is 4.5%, monthly deposit is $200, and time is 5 years.
Solve: Effective monthly rate = (1 + 0.045)^(1/12) – 1 = 0.3675%
Future account value = about $25,860.17
Total deposits = 10000 + (200 x 60) = $22,000
Interest earned = 25860.17 – 22000 = $3,860.17
Example 2: Find the result if the opening deposit is $25,000, APY is 3.8%, monthly deposit is $300, and time is 3 years.
Solve: Effective monthly rate = about 0.3113%
Future account value = about $39,369.29
Total deposits = 25000 + (300 x 36) = $35,800
Interest earned = 39369.29 – 35800 = $3,569.29
Example 3: Find the result if the opening deposit is $5,000, APY is 5.2%, monthly deposit is $150, and time is 10 years.
Solve: Effective monthly rate = about 0.4233%
Future account value = about $31,693.29
Total deposits = 5000 + (150 x 120) = $23,000
Interest earned = 31693.29 – 23000 = $8,693.29
Table of money market account calculator
| Opening Deposit | APY | Monthly Deposit | Future Account Value |
|---|---|---|---|
| $5,000 | 5.20% | $150 | $31,693.29 |
| $10,000 | 4.50% | $200 | $25,860.17 |
| $15,000 | 4.00% | $250 | $43,865.19 |
| $25,000 | 3.80% | $300 | $39,369.29 |
How to use this money market account calculator
Enter the opening deposit in the proper input field. After that, enter the APY, the monthly deposit amount, and the number of years. Then click the calculate button. The calculator will show future account value, total deposits, interest earned, and effective monthly rate in the result box.
This calculator is useful when comparing cash-saving strategies, emergency-fund plans, or short-to-medium-term savings goals. A money market account usually offers lower risk and easier access than many long-term investment products, but it still benefits from steady deposits and compounding over time. Looking at interest earned beside total deposits makes it easier to see whether a higher APY or a larger monthly deposit will make the bigger difference for your goal.
When using the result, remember that real account rates can change over time and that this calculator assumes a constant APY for the whole period. Banks may also impose balance rules, transfer limits, or variable promotional rates. Even so, this calculator gives a clear and practical estimate of how a money market account can grow with regular saving. It is useful for cash planning, savings comparison, emergency-fund review, and finance education.