How we get to
what you keep.

What this release covers

This is a public beta for taxable individual U.S. accounts. The calculator includes 22 verified rate observations across Fidelity, Vanguard, Schwab and Robinhood, plus your own savings APY. All 50 states and DC are selectable; state tax rates are entered by you. This is not a completed state-by-state tax rules engine or a complete inventory of available funds.

Home-platform access is used for the listed issuer funds, subject to your account and current prospectus. Cross-platform availability and E*TRADE ticker eligibility remain unverified. The core retail classes are included; premium and institutional classes remain in the research queue. Standard purchases and normal holding periods are modeled; special liquidity fees, brokerage service fees and early account closure fees are not.

The arithmetic

For a savings or cash APY, gross earnings equal balance × ((1 + APY)^(months / 12) − 1). For a money market fund’s annualized seven-day yield, we use balance × ((1 + yield / 12)^months − 1). Rates are entered as decimals in these formulas. We assume constant rates, monthly fund reinvestment, no deposits or withdrawals, and taxes paid from money outside the compared account.

After-tax earnings equal gross earnings minus federal tax, state tax, local tax, applicable NIIT and incremental product fees. Each tax uses its own taxable fraction. Quoted fund yields already reflect fund expenses and applicable waivers; we do not subtract the expense ratio again. We do not model tax deductions, credits, phaseouts, capital gains, changing brackets or the timing of estimated tax payments.

The HYSA break-even APY is the savings APY that would produce the same net dollars over the selected period with the entered tax rates. It includes the modeled product fee. It is blank when balance is zero or the product’s projected net earnings are negative.

Taxes: what is known and what is assumed

• Government-income percentages come from the issuers’ 2025 tax supplements and are proxies for 2026. They are eligible income percentages, not a forecast based on portfolio holdings.
• For California, Connecticut and New York, the fund-level eligibility flag is applied separately from the government-income percentage. A high annual percentage alone does not establish qualification.
• For other states, the model uses the issuer’s eligible government-income fraction. This is a general modeling assumption, not an independent verification of every state return or security classification.
• Vanguard’s municipal federal exemption and California/New York allocations use the linked 2025 documents. State allocation percentages describe exempt-interest distributions, not every possible distribution.
• Where a municipal fund’s federal distribution split is missing, we show mathematical bounds from taxable to exempt. An unknown state exemption also produces bounds from 0% to 100%. Neither endpoint is asserted to apply. For known state allocations but unknown federal splits, the lower bound claims no state exemption.
• National municipal restrictions are applied per issuer: CA/MN for Fidelity and Vanguard, NJ for Fidelity, and IL for all listed national funds. DC qualified municipal interest is modeled as state-exempt. FTEXX uses separate Indiana and Utah letters. Other unresolved cases remain ranges; see the coverage page. Prior-year restrictions remain assumptions for projections.
• Local tax is applied to all projected income at the user-entered rate with no exemption. Local exemption rules are outside this release.
• The optional 3.8% NIIT is applied to all modeled federally taxable earnings. This assumes those incremental earnings are fully subject to NIIT; income thresholds are not calculated.
• AMT is not computed. Selecting “AMT may apply” excludes municipal funds, including any fund with AMT in its name, because the user’s full AMT situation is outside this model.

Municipal ranges are excluded from rankings. “Highest estimate” means highest among the eligible products with complete model inputs, including your savings example. It does not establish that a product beats uncertain options or all products on the market.

Source dates and freshness

The latest data-review batch is 2026-09-06. Each product below has a separate source date and successful check date. A failed check does not advance that product’s date. APY freshness uses the review date; money market freshness uses the quote date. The live calculator removes quotes at eight calendar days of age. Article tables and worked examples rebuild from the same dataset and retain explicit dates; they are not streaming quotes.

There is no active automatic daily updater yet. A new issuer check, data validation, build and deployment are required to refresh this static release. The browser evaluates quote freshness when the calculator runs. Stale exclusion is a guard against missed updates, not proof of a working update service.

Risk and access

Money market mutual funds are investments, can lose value and are not FDIC insured. They are not the same as bank money market deposit accounts. A fund purchase may require a sale before cash can be withdrawn. Check settlement, redemption cutoffs, automatic liquidation eligibility and account restrictions at your brokerage.

Robinhood’s current program terms distinguish brokerage-held cash from bank-swept balances. The first $10,000 is held at the brokerage without FDIC insurance under the reviewed description; eligible amounts above it may receive pass-through bank deposit coverage subject to limits and conditions. The model subtracts $5 per month for Gold unless it is already owned. It does not model other subscription benefits or promotions.

Official source documents

• Vanguard money market rates, minimums and expenses
• Schwab money market rates and minimums
• Robinhood high-yield cash program and Gold terms
• Fidelity 2025 U.S. government securities income
• Fidelity 2025 municipal income by state
• Vanguard 2025 U.S. government obligations income
• Vanguard 2025 municipal income by state
• Vanguard 2025 federal tax-exempt income and AMT
• Schwab 2025 supplementary tax information
• IRS Publication 550
• IRS Topic 559

Read the coverage and verification status →

The dated quote register

Independence

Cash After Tax is an independent educational project. It is not affiliated with the listed brokerages or fund issuers. There are no affiliate links or paid placements in this release. It is not a brokerage, a tax preparation service or an investment adviser.