Cash Parking Calculator
A high-yield savings account, a money market fund, and a Treasury ETF can advertise the same rate and leave you with different amounts, because they carry different fees and are taxed differently by your state. Enter your cash, the current rates, and your state to see what each one keeps. Educational math only, no recommendation.
Your cash and tax settings
Treasury ETF
e.g. SGOV
Money market fund
e.g. SPAXX, VMFXX
High-yield savings
Bank account (FDIC)
Before you read the results: this is educational arithmetic, not financial or tax advice, and it recommends none of these options. It applies the fee, federal rate, and state rate you enter to the yields you enter. It ignores the 3.8% net investment income tax, the value of FDIC insurance, liquidity and settlement differences, promotional or teaser rates, and your full tax situation. Yields are not guaranteed and change with the Fed; money market funds and ETFs are not FDIC insured and can lose value. ETF BFF is not a registered investment adviser. Confirm current rates with each provider.
What $25,000 keeps in a year, at these settings
Treasury ETF
After fees & tax / year
–
Net-of-fee yield–
After-tax yield–
Money market fund
After fees & tax / year
–
Net-of-fee yield–
After-tax yield–
High-yield savings
After tax / year
–
Net-of-fee yield–
After-tax yield–
This is the math behind our most-read pages. The Expense Report covers cash, yields, and the tax mechanics in one clear email a week. Free, unsubscribe anytime.
What the settings mean
- Net-of-fee yield is the yield after the fund's expense ratio. A bank savings account has no fund fee; a Treasury ETF and a money market fund each subtract their expense ratio from the gross yield.
- State tax exemption applies to US Treasury interest. A Treasury ETF like SGOV passes nearly all of its income through exempt from state tax. A high-yield savings account is fully taxed. A money market fund depends on what it holds: Treasury-only funds are largely exempt, while prime and mixed government funds are mostly or fully taxed, as covered in the cash comparisons.
- Federal tax applies to all three at your ordinary bracket. None of these payouts are qualified dividends.
- Inside an IRA or 401(k), the tax differences disappear; every setting here describes a taxable account. The full picture is in how ETFs are taxed and the Treasury ETF guide.
Common questions
Does a Treasury ETF really keep more than a savings account?
It can, but not always, and this calculator shows when. Two things drive the difference at the same headline rate: the fund fee (a savings account has none, a Treasury ETF charges a small expense ratio) and state tax (Treasury interest is exempt from state income tax, while savings account and most money market interest is not). In a high-tax state the Treasury exemption often outweighs the fund fee; in a no-income-tax state it does not. The result depends entirely on your inputs.
Why does state tax change the comparison so much?
Interest from US Treasury securities is exempt from state and local income tax under federal law. A Treasury ETF like SGOV passes nearly all of its income through with that exemption. A high-yield savings account pays fully taxable interest, and a prime money market fund holding corporate paper keeps little to no exemption. The higher your state rate, the more that exemption is worth, which is why the same headline yield can rank differently in California than in Texas.
Are these yields guaranteed?
No. All three options pay rates that move with the Fed and can change at any time. A savings account APY can be cut by the bank, and money market and Treasury ETF yields float daily. This calculator uses the current rates you enter; it does not predict future yields. A savings account is FDIC insured up to limits, while money market funds and ETFs are not FDIC insured and can lose value.
Is this calculator financial advice?
No. It is an educational tool that applies fee and tax arithmetic to numbers you enter, and it recommends nothing. It simplifies: it ignores the 3.8% net investment income tax, FDIC insurance value, liquidity and settlement differences, promotional APYs, and your full tax situation. ETF BFF is not a registered investment adviser. Confirm current rates with each provider and your own situation with a tax professional.
Free one-page cheat sheet
Where should your cash actually sit?
One page comparing SGOV, T-bills, high-yield savings, money market funds, and CDs on yield, tax, liquidity, and safety. Save it, print it, keep it.
No spam · Unsubscribe anytime · Your download opens instantly
Open your Cash Parking Cheat Sheet →
Your download is ready above. We also emailed a confirmation link, click it to get The Expense Report, our weekly ETF newsletter.
Nothing on ETF BFF is personalized financial or tax advice, and this calculator makes no recommendation about any account, fund, or strategy. Results are hypothetical arithmetic based only on the numbers you enter. A high-yield savings account is FDIC insured up to applicable limits; money market funds and ETFs are not FDIC insured, are not bank guaranteed, and may lose value. Yields are not guaranteed and change over time. Tax rates and rules change. ETF BFF is not a registered investment adviser. Past performance does not guarantee future results. See our About page for full disclosures.