Apportionment formula (receipts factor)

To calculate your Washington taxable income, multiply your apportionable income from each apportionable activity by the receipts factor for that apportionable activity.

This formula is:

Washington taxable income = Apportionable income X Receipts factor

Receipts factor

The receipts factor is a fraction.

• The numerator is total gross apportionable income attributed to Washington during the current tax year.
• The denominator is the total gross apportionable worldwide income during the current tax year minus throw-out income.

Receipts factor = Gross apportionable income attributed to Washington / (Worldwide gross apportionable income – Throw-out income)

Reporting current periods

When filing your excise tax returns, you can estimate Washington taxable income based on information from the most recent complete calendar year, or you may use the current year. In both cases, you must later correct your reporting by filing an Annual Reconciliation of Apportionable Income.

Correcting prior periods

You may amend your returns to correct apportionable income on returns within the current calendar year. After the close of the calendar year, you must correct apportionable income by filing the annual reconciliation. Amended returns filed to correct apportionable income for periods outside the current calendar year will be rejected.

Note: If you discover you have incorrectly reported a period in the current calendar year, you should amend those periods. Adjusting other periods or waiting until you file the annual reconciliation may lead to additional penalties.