Money Market Calculator
Calculate your money market account (MMA) earnings with our free calculator. Money market accounts combine higher interest rates with limited check-writing privileges, offering a middle ground between regular savings and CDs for savers who want better returns with some accessibility.
Money Market vs Other Savings Options
| Account Type | APY Range (2024) | Liquidity | FDIC Insured | Minimum |
|---|---|---|---|---|
| Regular Savings | 0.01-0.50% | Unlimited | Yes | $0-$100 |
| Money Market | 4.00-5.00% | Limited (6 transactions) | Yes | $1,000-$10,000 |
| High-Yield Savings | 4.50-5.25% | Unlimited | Yes | $0-$100 |
| CD | 4.50-5.30% | Locked | Yes | $500-$1,000 |
Money Market Account Features
- Check-writing ability: Write checks from your account (limited)
- Debit card access: Some MMAs include ATM cards
- Higher minimums: Often require $1,000-$10,000 minimum
- Tiered rates: Higher balances may earn better rates
Money Market Calculator
``javascript
function calculateMoneyMarket(principal, apy, months, monthlyDeposit = 0) {
const monthlyRate = apy / 100 / 12;
let balance = principal;
for (let m = 0; m < months; m++) {
balance = (balance + monthlyDeposit) * (1 + monthlyRate);
}
const totalDeposits = principal + (monthlyDeposit * months);
const interestEarned = balance - totalDeposits;
// Check if meeting typical minimum balance requirements
const meetsMinimum = balance >= 2500;
return {
finalBalance: balance.toFixed(2),
totalDeposits: totalDeposits.toFixed(2),
interestEarned: interestEarned.toFixed(2),
meetsTypicalMinimum: meetsMinimum
};
}
`
MMA vs High-Yield Savings
For most savers, high-yield savings accounts now offer comparable or better rates than MMAs without minimum balance requirements. MMAs remain useful if you specifically need check-writing access to your savings or if your bank offers tiered rates that reward higher balances.
The Projection Behind This Page
Starting from $10,000, adding $200 a month at 7%:
| Year | Deposited | Balance | Growth | Growth on deposits |
|---|---|---|---|---|
| 1 | $12,400 | $13,201 | $801 | 6% |
| 5 | $22,000 | $28,495 | $6,495 | 30% |
| 10 | $34,000 | $54,714 | $20,714 | 61% |
| 20 | $58,000 | $144,573 | $86,573 | 149% |
After 20 years, 60% of the balance is growth rather than money you
put in. That crossover — the point where returns exceed contributions — is the whole reason
compounding is worth waiting for, and it arrives later than most people expect.The Formula
`
A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) ÷ (r/n)]
└── initial principal ──┘ └────── regular contributions ──────┘
`
The second term usually dominates. On these numbers the $200 monthly contribution
accounts for the larger share of the final balance, which is the practical lesson: how much
you add matters more than the rate, right up until the balance gets large.
How Long Until It Doubles
The Rule of 72 divides 72 by the rate to estimate doubling time. At 7%:
`
72 ÷ 7 = 10.3 years
`
The exact answer is 10.2 years — the rule is accurate to within a few months
for rates between 6% and 10%, and drifts at the extremes. It works because ln(2) ≈ 0.693 and
72 has convenient divisors.
| Rate | Rule of 72 | Exact |
|---|---|---|
| 2% | 36.0 yr | 35.0 yr |
| 5% | 14.4 yr | 14.2 yr |
| 7% | 10.3 yr | 10.2 yr |
| 10% | 7.2 yr | 7.3 yr |
| 15% | 4.8 yr | 5.0 yr |
Compounding Frequency at This Rate
A nominal 7% turns into a different effective yield depending on how often it
compounds — this page uses daily:
| Compounded | Effective annual yield |
|---|---|
| Annually | 7.000% |
| Quarterly | 7.186% |
| Monthly | 7.229% |
| Daily | 7.250% |
| Continuously | 7.251% |
The gap between annual and monthly is worth having. The gap between monthly and daily is
0.021 percentage points — rounding. Compare accounts on
APY, which already folds the frequency in, rather than on the nominal rate.Inflation Is the Number That Matters
A 7% nominal return against 3% inflation is a 4.0% real return.
Real return is what buys anything:
`
real ≈ nominal − inflation
``
Over 10 years, 3% inflation cuts purchasing power by about 26%. A projection quoted in nominal dollars therefore overstates what the money will actually be worth, which is why retirement targets are usually stated in today's dollars.