Limitations
This is an educational estimate, not tax or financial advice — and its accuracy claim is specific: the headline income figure is verified to be within 2% of a correct manual computation within the scope described below. Outside that scope, here's what we knowingly don't model yet.
Not modeled at all
- Tax credits and phaseouts (Child Tax Credit, EITC, etc.)
- Itemized deductions — we use the standard deduction only
- Alternative Minimum Tax (AMT)
- Capital gains tax
- Self-employment tax
- Multi-state income allocation (living in one state, working in another)
- Dependents or household size adjustments
- Local/municipal income tax (NYC, Philadelphia, Ohio and Maryland localities, etc.) — state-level only for now
- Markets outside the United States
Filing status accuracy
Single and married-filing-jointly are the two statuses we've verified state by state. Every state's joint-filer brackets were individually checked against published sources in August 2026.
- Head of household and married-filing-separately are not fully verified. For most states we apply the single-filer brackets to these statuses, because no source we could access publishes distinct schedules for them. Head-of-household brackets are generally wider than single, so where they differ, this site overstates your tax rather than understating it.
- California specifically: its head-of-household schedule is real and differs from single, but the state's own rate-schedule page blocks automated access and the secondary sources we found disagreed with each other. Rather than pick one, we left it flagged.
- Several states' standard deductions could not be located and are modeled as $0, which also overstates tax. Where a state uses a sliding-scale deduction that phases out with income (Wisconsin, Rhode Island), we don't model the phaseout.
Modeled with a documented simplification
- Sales tax uses a representative county per state today, not full ZIP-level precision (a planned future upgrade)
- Vehicle- and home-specific fees (doc fees, registration, transfer tax) are currently only verified for Texas and California — other states will show an error until that data is added
- PMI, mortgage points, and adjustable-rate mortgages are not modeled for home purchase
- Resort fees and other property-specific hotel charges are not modeled
- Opportunity cost and multi-year depreciation/appreciation figures are forecasts — genuinely uncertain by nature, not a precision gap
- Some categories (cannabis, concert tickets, streaming, gym memberships, and others with real per-state taxability variance) model the majority treatment with specific documented state exceptions in their own assumptions, rather than a full 51-state rule set
Data freshness
Tax brackets and rates are current for the 2026 tax year as of this site's last data update. Federal brackets and FICA figures are re-verified annually each fall when the IRS publishes the next year's numbers; a stale dataset is a bug, not a policy — if you spot one, use the "report an error" option (coming soon) or check the as-of date shown for each figure.