Washington state income tax
Last updated: 2026-04-27
TL;DR / ELI5
Primary form: —
BasilTax engine: Not yet — federal plus manual state review
Structure: No state income tax
No state income tax; capital gains excise may apply to certain high earners.
Washington income tax at a glance
This guide explains how Washington fits into your overall filing picture. Your federal Form 1040 is only half the story—states add their own definitions, subtractions, credits, and withholding rules.
Because Washington has no broad-based wage income tax, many residents will not file a traditional state income tax return for wages. No state income tax; capital gains excise may apply to certain high earners.
Withholding and W-2 boxes
If you work in Washington (or your employer withholds for Washington), compare boxes 15–17 on your Form W-2 to what you expect on the state return. Mismatches here are a common source of balance due surprises.
Credits, deductions, and quirks
State returns often start from federal adjusted gross income (AGI) and then apply state-specific subtractions, additions, credits, and alternative minimum taxes. Read your state instructions for the exact list—this page is a hub, not a substitute for official guidance.
Verification workflow
Upload your PDFs, assign them to a return, and run compute. When BasilTax supports Washington end-to-end, you can trace state lines to the same documents you used for federal. When support is still in progress, use BasilTax to lock down federal and broker schedules first, then complete Washington manually with confidence.
Ready to tie every line to your documents?
Upload your W-2s and 1099s—BasilTax extracts fields, computes federal and state, and explains each number with citations.
Frequently asked questions
- Does Washington have a state income tax?
- Washington does not impose a broad-based individual wage income tax like many states. No state income tax; capital gains excise may apply to certain high earners.
- What form do I file for Washington?
- Most residents use — for the state return, subject to exceptions for part-year residents and special situations. Always confirm the latest state instructions each filing season.
- Does BasilTax calculate Washington state tax?
- BasilTax is focused on federal accuracy for Washington today; you should still review state-specific rules and forms outside the app until engine support ships.