How we verify
One engine does all the math, and this is what it has been checked against.
What the tests cover
The tax engine carries 3,500+ automated tests, and this is what they are about.
ISO exercises and sales, RSU vests, ESPP purchases, NSO exercises, and plain share sales.
AMT: when an exercise triggers it, and how the credit it creates comes back to you in later years.
Each area runs across a range of incomes, filing statuses, and states.
What the numbers are checked against
One real filed 2025 federal return, reproduced line by line: taxable income, AMT, the AMT credit, and the total tax.
Two figures on that return are not modeled, a $9 qualified business income deduction and a $5 foreign tax credit.
A full dummy return, prepared in a leading commercial tax product, matched the engine on every federal line compared.
The IRS's own worked examples: Publication 525, Publication 550, Form 6251, Form 8801, and Form 8949.
Who has checked it
PreTaxed is pre-alpha, and no outside CPA firm has audited the engine.
Not tax advice. Estimates only. Consult a qualified CPA or tax advisor before acting.
Tax years
Federal: 2022 through 2026.
California: 2023 through 2026. Colorado and Washington: 2024 through 2026.
State coverage and caveats
California, Colorado, and Washington have state-specific models.
Washington levies no income tax but does tax some capital gains, which is why it needs its own model.
Eight no-income-tax states compute as zero: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, and Wyoming.
Any other state is not calculated at all, so your figures there are federal only.
The owed card on your dashboard says the state is not calculated, rather than showing a zero.
Known limits
California AMT is not modeled.
When your year carries ISO exercise spread, three places name that gap with a rough size for what is missing.
They are the dashboard notice, the home-page calculator, and the packet you copy for your AI.
With no ISO spread there is nothing missing, so that note does not appear.
Some 2026 California, Colorado, and Washington figures are estimates until those states publish final tables, and the dashboard notice says so.
The AI boundary
AI never calculates.
The engine does the math, and AI can only explain a result the engine already produced.