Key IRS and Washington State Tax Deadlines: When to File and What to Know
Staying on top of tax deadlines is one of the most important parts of keeping your finances on track. Whether you’re a W-2 employee, a freelancer, or a small business owner, missing a due date can lead to penalties, interest charges, or lost refunds. To help you avoid surprises, this guide outlines the most important IRS and Washington State tax deadlines you should know, including quarterly estimated tax payments, extension filings, and state obligations.
At Linda’s Tax Service in Vancouver, WA, our accountants, bookkeepers, and tax professionals help individuals, gig workers, retirees, and small business owners stay compliant and stress-free all year long. Use this overview to plan ahead and make sure you never miss a filing.
Key Federal IRS Tax Deadlines
Annual Federal Tax Filing Deadline — April 15
For most U.S. taxpayers, April 15 is the deadline to file their Form 1040 federal tax return for the previous tax year.
If April 15 falls on a weekend or holiday, the IRS adjusts the due date accordingly.
What’s due on this date:
- Individual income tax returns
- Balance due payments
- First-quarter estimated taxes for self-employed individuals
- Deadline to contribute to traditional and Roth IRAs
Quarterly Estimated Tax Deadlines
Freelancers, independent contractors, landlords, and small business owners often must make quarterly estimated tax payments to cover federal income tax and self-employment tax.
Estimated taxes are due on:
- April 15 — 1st Quarter
- June 15 — 2nd Quarter
- September 15 — 3rd Quarter
- January 15 (following year) — 4th Quarter
Tip: If you have uneven income, common among gig workers, the IRS allows you to use an annualized income method to match taxes more accurately to your earnings.
Federal Tax Extension Deadline — October 15
If you need more time to file your return, you can request a six-month extension by filing Form 4868 by April 15.
Important:
A tax extension gives you more time to file, but not more time to pay. Any tax owed must still be paid by April 15 to avoid interest and penalties.
Washington State Tax Deadlines
Although Washington does not have a state income tax, residents and business owners still must meet certain obligations. Here are the key deadlines for residents and business entities.
Washington B&O and Sales Tax Reporting
Small businesses, LLCs, freelancers, and sole proprietors operating in Washington may owe Business & Occupation (B&O) tax and possibly sales tax.
Washington’s Department of Revenue (DOR) assigns filing frequencies:
- Annual Filers: Due January 31
- Quarterly Filers: Due the last day of the month following the quarter (April 30, July 31, Oct 31, Jan 31)
- Monthly Filers: Due the 25th of the following month
If you are unsure of your frequency, you can check your DOR business license or MyDOR account.
Washington Business License Renewals
Many businesses must renew state licenses every year, typically by the expiration date listed in their account.
Renewal notices are sent by the DOR, but it’s smart to check proactively.
Property Tax Deadlines
If you own property in Washington:
- First installment due: April 30
- Second installment due: October 31
Property taxes are paid to your county treasurer, not the IRS or DOR.
Special Deadlines for Businesses & Self-Employed Individuals
LLC, Partnership & S-Corp Deadlines — March 15
For pass-through entities:
- Form 1120-S (S corporations)
- Form 1065 (partnerships)
are due March 15.
Extensions push the deadline to September 15.
C-Corporation Deadline — April 15
C-corporations file Form 1120 and may request an extension until October 15.
Why Staying Ahead of Deadlines Matters
Staying organized and filing on time helps you:
- Avoid penalties and interest
- Protect potential refunds
- Keep business accounts in good standing
- Reduce stress during tax season
- Ensure accurate quarterly tax planning
At Linda’s Tax Service, we help clients track deadlines and stay compliant with both state and federal rules.
Contact Us for Tax Deadline Help
If you’re unsure which deadlines apply to you, or if you need help preparing returns, filing extensions, or calculating estimated taxes, our team is here for you.
Contact us today! We help individuals, freelancers, side-gig workers, and small business owners stay compliant and maximize their savings.