Washington B&O versus federal income tax: why profit is not the same tax base

The three questions owners often combine

“How much tax does my business owe?” is usually several questions. First, what does the business report to Washington? Second, what federal returns and owner-level obligations apply? Third, does a city such as Seattle require a license or a return? A single profit figure does not answer all three. The useful first step is to name the tax and jurisdiction before discussing a rate or a deduction.

Washington DOR describes B&O as a gross receipts tax and states that ordinary business costs such as labor and materials are not deductions from that base. Specific statutory deductions, exemptions and credits can still apply. The federal income tax system is different, and the IRS connects the form of business with the taxes and returns it must handle. Neither system can be completed by copying one unexplained total out of a bank account.

• Washington DOR: Business and occupation tax
• IRS: Business taxes
• Washington DOR: Frequently asked questions about B&O and gross business income

A gross-receipts example that does not invent a tax bill

Consider a fictional business with $180,000 in sales and $140,000 of recorded operating costs. Its simple management calculation produces $40,000 before other adjustments. That arithmetic is useful for asking whether the business model is working. It is not a Washington B&O calculation, and it is not enough information to calculate the business’s or owner’s federal tax.

For the state analysis, begin with the receipts and determine the applicable activity, sourcing and any permitted adjustments or credits. For federal work, review the entity, accounting method and the treatment of the costs. For a city, review the city’s own jurisdiction and rules. This example deliberately does not multiply the figures by a single rate: doing so would hide the information that actually determines the answer.

When reviewing your own numbers, keep the management calculation and the tax calculation side by side. If they differ, label the bridge. An owner should be able to ask why a number changed without receiving only a final tax amount. A clear bridge also makes it easier to update a forecast when a new activity, location or business arrangement begins.

Start the state analysis with what the business actually does

A business may have more than one revenue stream. Selling products, performing construction and providing another service should not automatically be grouped under the same label. DOR’s B&O classifications depend on the activity, and a small-business credit can reduce or eliminate liability for an eligible business. Eligibility and the computation need to be checked; “small” is not a universal exemption.

A practical revenue map has one row per activity, not one row per bank account. Add the invoice description, where the work or sale occurred, customer or delivery location where relevant, amount, reporting period and the evidence supporting a classification. A sales report should let a reviewer trace the total back to transactions rather than rely on a category named consulting, other income or online sales.

• Washington DOR: Business and occupation tax

Identify the federal return before asking about deductions

A sole proprietor’s business income or loss is generally reported using Schedule C with the individual return, while other business structures can have different federal returns and reporting relationships. The IRS’s Schedule C page describes its use for a sole proprietorship. Confirm the actual federal status rather than assuming every LLC, trade name or side business files the same form.

Prepare a short entity summary for the tax preparer: formation records, ownership, elections supplied by the owner, prior-year filed returns and any changes. If an owner says “we became an S corporation,” ask for the documents and effective date for review. Do not resolve the question by renaming an account in the bookkeeping file. A tidy file is still incomplete if it describes the wrong taxpayer.

• IRS: About Schedule C (Form 1040)

Seattle’s 2026 change is a city rule

Effective January 1, 2026, Seattle’s B&O system uses a $2 million tax threshold and a standard deduction of up to $2 million under its city rules. The city states that businesses under the threshold must still file their Seattle B&O returns. The threshold is not a Washington state B&O threshold and does not erase federal reporting.

The Seattle Shield guidance says an annual filer’s 2026 city B&O return is due April 30, 2027. That statement concerns annual Seattle city returns. Check the actual city filing assignment, current guidance and any relevant account notice; do not transplant this date into Washington DOR or federal calendars. If your business crosses city boundaries, gather the location and activity evidence before deciding what belongs in the city calculation.

• City of Seattle: Seattle Shield B&O tax changes
• City of Seattle: Director’s Rule 5-013, threshold and standard deduction

Sales tax needs a separate reconciliation

For a business that makes taxable retail sales, the sales-tax question is different again. Avoid using a net bank settlement as the only sales record. A payment processor can settle sales after withholding fees, and a deposit can include amounts that need separate accounting. Preserve the source sales report, tax columns, refunds and settlement statement so the preparer can identify the correct reporting amounts.

Use separate review columns for business receipts, tax collected, refunds, processor fees and money transferred to the bank. This is a practical reconciliation design rather than a taxability determination. Taxability, collection responsibility and location rules depend on the transaction and need their own review. An expense labelled fees does not explain whether a tax obligation was handled properly.

Forecast cash using several obligations, not one percentage

Build a cash forecast with separate lines for expected federal payments, state excise liabilities, city liabilities and other obligations that actually apply. Mark estimates as estimates. Record who last reviewed each assumption and when. A growing business can have more money arriving while also creating new reporting work, so a comfortable bank balance is not evidence that all of it is available to spend.

For a quarterly review, compare actual sales by activity with the forecast, identify new products or locations, reconcile payments already made and save agency confirmations. Ask the preparer to explain large changes before the next due date. This process produces better decisions than reserving one permanent percentage of deposits and assuming it covers every jurisdiction.

If you ask Aldro for tax filing or bookkeeping help, bring the revenue map and entity summary. Confirm the returns covered in writing. An advertised US$399 filing offer does not establish that every state excise return, city return, owner return or prior-period correction is included.

• Which entity or owner owes each payment?
• Which agency and reporting period does the payment cover?
• What source records support the tax base?
• Who confirms filing acceptance and payment completion?