October is a good time to shift from filing deadlines to year-end planning. With three months left in 2026, a little cleanup now can make tax season smoother and give you more time to act on decisions that may affect this year's return.
Here are a few practical items for Seattle-area business owners and families to put on the fall checklist.
Give your books a fall checkup
Before year-end gets busy, review your bookkeeping through September. Reconcile bank and credit-card accounts, make sure business and personal expenses are separated, and follow up on missing receipts or uncategorized transactions.
For business owners, this is also a useful time to compare year-to-date profit with what you expected. A clearer picture of 2026 income can help with estimated-tax planning and other year-end decisions.
Washington quarterly filers: mark your calendar
If your business files Washington excise tax returns quarterly, the third-quarter 2026 return covers July through September. Washington's Department of Revenue says quarterly returns are generally due at the end of the month following the quarter, with weekend and holiday adjustments.
Check your My DOR account for the filing and payment date that applies to you, especially if you use electronic payment. Monthly and annual filers follow different schedules.
Look ahead to your final 2026 estimated tax payment
For calendar-year individuals who make federal estimated tax payments, the fourth 2026 installment is generally due January 15, 2027. Estimated payments can apply to self-employment income, investment income and other income that does not have enough tax withheld.
If your income or deductions changed significantly this year, it may be worth reviewing your projection before the final payment rather than simply repeating an earlier amount.
Know the 2026 standard deduction
For 2026 federal income taxes, the IRS lists the standard deduction as $32,200 for married couples filing jointly, $16,100 for single filers and married individuals filing separately, and $24,150 for heads of household.
The standard deduction is the amount many taxpayers subtract from income instead of itemizing individual deductions. Whether itemizing makes sense depends on your own expenses and tax situation.
Start gathering year-end information now
Businesses can save time later by reviewing vendor records, payroll information and fixed-asset purchases before December. Families may want to gather records for charitable gifts, major life changes, investment activity and other items that could affect their return.
You do not need to assemble a complete tax package in October. The goal is simply to identify gaps while there is still time to find documents or ask questions.
Every tax situation is different, and general reminders are not a substitute for individual advice. If you would like to review your 2026 tax picture or year-end planning opportunities, please contact Magnolia CPA so we can discuss your situation.
Magnolia CPA · October 2026
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