Jump to: Tax Calculator MMF Yields Table Compounding Notes Constant NAV ($1) Muni Exemptions

Money Market Fund (MMF) Yields & After-Tax Calculator

Compare yields across the most popular Money Market Funds from Vanguard, Fidelity, and Schwab, as well as cash-equivalent and municipal bond ETFs. Enter your tax information below to dynamically compute the after-tax effective compound yield in real time.

Yields are automatically refreshed from my rate scraper backend published on GitHub.

When comparing these yields to bank deposit products (high-yield savings accounts, CDs, etc.), remember to discount those bank rates by your marginal Federal and State income tax rates for an apples-to-apples comparison.

Tax Settings:

Federal:

State:

State Rate:

NIIT:

Fund	Type	Fed Tax	State Tax	Updated	SEC Yield	Compound	After-Tax	Duration	NAV $1	Notes

SEC 7-Day vs. 30-Day Compounding Calculations

Money Market Funds report an annualized 7-day SEC yield reflecting the dividend rate of the portfolio over the past week net of expense ratios. Because MMF dividends accrue daily and compound into share purchases monthly, the annual effective compound yield is computed according to the standard SEC formula:

Compound Yield = (1 + SEC_Yield × 7 / 365)^(365 / 7) - 1

For ETFs (such as Treasury bill and bond ETFs), yield is reported as a 30-day SEC yield. Because ETF dividends already reflect monthly reinvestment and trade on secondary exchanges with market price fluctuations, compound yield is presented as the annualized 30-day yield directly.

Constant NAV ($1.00) vs. Floating NAV

Yes: Retail and government money market funds maintain a constant Net Asset Value of $1.00 per share by adjusting the dividend payout rather than changing the share price. Historically, "breaking the buck" has occurred only twice in 50 years, both times involving commercial paper default rather than US Treasuries.

Kinda: Ultra-short Treasury bill ETFs (such as USFR, TFLO, SGOV, VBIL) hold ultra-short obligations. Their share prices fluctuate by pennies throughout each monthly distribution cycle as interest accrues, but they maintain minimal interest rate risk.

No: Bond ETFs with multi-year durations (such as USHY, INMU, MUB, VTEB) have floating share prices and significant duration risk. If interest rates rise, bond prices fall. These are not money market funds and should not be treated as cash sweep substitutes.

State Tax Exemptions for Municipal Funds

Interest earned on US Treasury obligations (e.g. VUSXX, FDLXX, SNSXX, SGOV) is legally exempt from state and local income taxes under federal law. Conversely, municipal bond funds are exempt from federal income taxes (0% Fed Taxable).

Single-state municipal funds (such as California's SWKXX, CALI, CMF and New York's SWYXX, NYF) offer double tax exemption (federal and state) only for verified residents of those specific states. In this calculator, single-state funds automatically adapt based on your selected state of residence.

Target Date Bond ETFs

Looking for fixed-maturity bond investments to lock in yields for a planned future expenditure? Check out the Interactive Target Date Bonds Calculator to compare after-tax yields across US Treasuries, TIPS, Municipals, and Corporate bond ETFs.