If you're parking cash in a money market account, this calculator shows exactly how much interest you'll earn — monthly, yearly, and over your full term — before you commit to an account. Top rates in May 2026 hit 4.01% APY. The national average is just 0.57%.
✓ Verified: FDIC & Bankrate — May 2026 | National avg MMA rate: 0.57% | Top rate: 4.01% APY
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Total Interest Earned
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⚠️ Disclaimer: This calculator provides estimates based on a fixed APY. Actual money market rates are variable and change with the Federal Reserve benchmark rate. FDIC insurance covers up to $250,000 per depositor per institution. This is not financial advice.
Sources & Methodology
✓ Formulas verified against FDIC compound interest guidelines. National average rate and top rates sourced from Bankrate and Yahoo Finance MMA surveys, May 2026.
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FDIC — Money Market Deposit Account Guidelines
fdic.gov — Official FDIC definitions, $250,000 insurance limit, and compound interest calculation standards for MMAs.
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Bankrate — Best Money Market Account Rates, May 2026
bankrate.com — Current MMA APY benchmarks, lender survey methodology, and rate comparison data updated May 2026.
Formula: Balance after n months = P × (1 + APY/12)^n + C × [((1 + APY/12)^n − 1) / (APY/12)]
where P = initial deposit, C = monthly contribution, n = months.
APY already accounts for daily compounding. Interest earned = Final Balance − Total Contributions.
Last reviewed: May 2026
How Money Market Account Interest Is Calculated
You open a money market account expecting it to grow. But there's a gap between what most people expect and what they actually earn — because they're at the wrong bank. The national average MMA rate is 0.57% per the FDIC. The top online bank rate as of May 2026 is 4.01% APY. On $50,000, that gap is $1,722 per year. Same deposit, same insurance, same liquidity — just a different institution.
Money market interest compounds daily in most accounts and credits monthly. The APY (Annual Percentage Yield) captures the full compounding effect, making it the only number that matters when comparing accounts. Never compare the stated interest rate — always compare APY.
Money Market APY Formula — Worked Example First
Monthly Interest = Principal × (APY ÷ 12)
$50,000 at 4.0% APY (top online bank rate):
Monthly = $50,000 × (0.04 ÷ 12) = $50,000 × 0.003333 = $166.67/month
Year 1 total = $166.67 × 12 = $2,000 interest earned
Same $50,000 at 0.57% APY (national average):
Monthly = $50,000 × (0.0057 ÷ 12) = $23.75/month
Year 1 total = $285 interest earned Gap: $1,715 per year from simply choosing the right bank
Best Money Market Account Rates — May 2026
Bank / Account
APY
Min Balance
Check Writing
TotalBank Online MMA
4.01%
$2,500
Yes
Brilliant Bank Surge MMA
4.00%
$1,000
Yes
EverBank Performance MMA
3.90%
$0
Yes
Ally Bank MMA
3.10%
$0
Yes
Traditional bank (avg)
0.57%
$1,000–$10,000
Yes
The gap between the best available rate (4.01%) and the national average (0.57%) is 3.44 percentage points. On $100,000, that gap costs you $3,440 per year. There is no meaningful difference in safety — both are FDIC insured to the same $250,000 limit. The only difference is where you bank.
What People Get Wrong About MMA vs. High-Yield Savings
Most people assume money market accounts always beat high-yield savings accounts. In 2026, that's often not true. Top HYSAs from online banks frequently match or exceed MMA rates, sometimes with lower minimums and no transaction limits. The real advantages of an MMA are check-writing access and a debit card — both useful if you need to access funds without a transfer delay. If you won't be writing checks, compare specific current rates rather than account types.
💡 MMA vs. money market fund — the confusion that costs people money: A money market account at a bank is FDIC insured and cannot lose principal. A money market mutual fund is an investment product — not FDIC insured. In 2008, the Reserve Primary Fund "broke the dollar" (fell below $1 NAV), causing losses for investors who thought they were in a safe bank account. If someone calls it a "money market fund" or it's held at a brokerage, it is not the same thing as a bank MMA.
How Much Does Your Balance Actually Earn? Real Numbers
Interest Earned at 4.0% APY by Balance and Term
Balance
Monthly Interest
Year 1 Interest
5-Year Balance
5-Year Gain
$10,000
$33/mo
$400
$12,214
$2,214
$25,000
$83/mo
$1,000
$30,535
$5,535
$50,000
$167/mo
$2,000
$61,070
$11,070
$100,000
$333/mo
$4,000
$122,140
$22,140
$250,000
$833/mo
$10,000
$305,350
$55,350
These figures assume 4.0% APY with no additional contributions. The 5-year compounding effect is real but not dramatic on its own — what accelerates growth significantly is adding monthly contributions. Adding $200/month to a $25,000 MMA at 4.0% APY turns it into approximately $52,700 over 5 years, versus $30,535 without contributions.
The Fed Rate Risk — Why Your MMA Rate Won't Stay This High
The Federal Reserve cut rates three times in 2024 and three times in 2025, then held rates steady in early 2026. Money market rates follow the federal funds rate closely — when the Fed cuts, your MMA rate drops within weeks, sometimes within days. You have no rate protection. Every dollar earning 4.0% today could be earning 3.0% or 2.5% within 12 months if the Fed resumes cutting. This is the core risk of MMAs: total liquidity, zero rate certainty.
⚠️ The CD ladder strategy for falling rates: If you have savings beyond your 3–6 month emergency fund in a MMA, consider moving a portion into 12–24 month CDs now to lock in current rates. Keep the emergency fund in the MMA for liquidity. Roll the CDs as they mature and assess rates at that point. This protects against rate drops on the portion you can afford to set aside, while keeping full access to the core emergency reserve.
MMA Decision Guide — When to Use One, When to Look Elsewhere
When a Money Market Account Makes Sense
A money market account is the right tool when you need both yield and liquidity on a meaningful sum. Emergency fund over $10,000: MMA at a top online bank. Down payment savings you'll need within 1–3 years: MMA or short-term CD. Business operating reserves: MMA provides check-writing access for occasional large payments. Cash sitting in a checking account earning nothing: move it to a MMA immediately — the difference between 0% in a checking account and 4.0% in an MMA on $50,000 is $2,000/year with zero added risk.
When to Look at CDs Instead
If you know you won't need the money for 12, 18, or 24 months, a CD locks in today's rate and protects against Fed cuts. The trade-off is an early withdrawal penalty (typically 90–180 days of interest) if you need the money early. In May 2026, top 12-month CD rates run 4.0–4.5% — comparable to top MMA rates, with the rate guaranteed for the full term.
FDIC Insurance — The $250,000 Limit and What Most People Miss
FDIC insurance covers $250,000 per depositor, per institution, per ownership category. A married couple can hold $500,000 in joint accounts at one bank and have it fully covered. Individual + joint + retirement accounts are each counted separately. If you have more than $250,000 in cash savings, spread it across multiple FDIC-insured institutions — not multiple account types at the same bank. Some institutions like Merchants Bank offer additional private deposit insurance beyond the FDIC limit for large deposits.
💡 Rule of 72 check: Divide 72 by your APY to estimate years to double your money. At 4.0% APY: 72 ÷ 4 = 18 years to double. At the national average 0.57%: 72 ÷ 0.57 = 126 years to double. This is why choosing the right institution matters so dramatically over any meaningful time horizon.
Frequently Asked Questions
Multiply your balance by the APY and divide by 12 for monthly interest. Example: $50,000 x 4.0% / 12 = $166.67/month. For compound growth over multiple years: Balance = Principal x (1 + APY/12)^months. APY already accounts for daily compounding, so this formula gives accurate results.
The national average MMA rate is just 0.57% per the FDIC, but top online banks offer up to 4.01% APY as of May 2026. TotalBank leads at 4.01%, Brilliant Bank at 4.0%, EverBank at 3.9%, and Ally at 3.1%. Traditional banks average below 1%. Always shop online banks for competitive rates.
Yes. Money market deposit accounts at FDIC-insured banks are covered up to $250,000 per depositor per institution. Credit union MMAs are insured by the NCUA for the same amount. Money market mutual funds are NOT FDIC insured and carry market risk — this is a critical distinction many people miss.
Most money market accounts compound interest daily and credit it monthly. The APY figure already accounts for the compounding frequency, so using APY in calculations gives accurate results without needing to know the specific compounding schedule.
At 4.0% APY, $100,000 earns $4,000 per year or $333 per month. At the national average of 0.57%, the same balance earns only $570 per year — $3,430 less annually for the exact same deposit. After 5 years at 4.0% APY, $100,000 grows to approximately $122,140.
A money market account is a bank deposit insured by the FDIC up to $250,000 — it cannot lose principal. A money market fund is an investment product not covered by the FDIC. In 2008, the Reserve Primary Fund fell below $1 NAV ("broke the dollar"), causing losses. If it's at a brokerage and called a "fund," it is not the same as a bank MMA.
Not automatically. In 2026, top HYSAs often match or beat MMA rates with lower minimums and no transaction limits. The real advantage of an MMA is check-writing and debit card access for large, occasional payments. If you won't be writing checks, compare specific current rates at each institution before choosing.
The Fed cut rates three times in 2024 and three times in 2025, then paused in 2026. MMA rates track the federal funds rate — if the Fed cuts again, your MMA rate drops within weeks. There is no rate protection. Consider laddering some savings into CDs to lock in current rates on the portion you can afford to tie up.
Minimums vary widely. Ally and Sallie Mae have no minimum. EverBank requires no minimum. CFG Bank requires $1,000. Traditional banks typically require $1,000 to $10,000. High-yield or jumbo MMAs may require $25,000 or more for the best advertised rates. Always check whether a minimum is required to avoid monthly fees.
Yes. Unlike CDs, money market accounts accept deposits at any time. Adding $200/month to a $25,000 MMA at 4.0% APY grows it to approximately $52,700 over 5 years — versus $30,535 without contributions. Regular contributions are the single most impactful way to accelerate MMA growth.
Federal Regulation D historically capped MMA withdrawals at 6 per month. The Federal Reserve suspended this in 2020, but many banks still enforce their own limits and charge excess withdrawal fees. Check your specific account agreement — limits vary significantly by institution.
When the Fed cuts rates, your MMA rate drops — often within the same statement cycle. There is no rate protection unlike a CD. In a falling rate environment, laddering some savings into CDs while keeping your emergency fund in the MMA is the standard approach to protect against future drops.
Yes. Money market account interest is taxable as ordinary income in the year it is credited. Your bank issues a 1099-INT for interest over $10. MMA interest is taxed at your marginal federal and state income tax rate — there is no special tax treatment unlike municipal bond interest.