Northline Tax Advisors Call (206) 555-0148
Small business tax Seattle, WA

The calm before the deadline.

Northline Tax Advisors PLLC is a small business tax and accounting firm in Seattle, Washington, run by two CPAs.

Deadline board

As of

Typical federal estimated tax dates; confirm yours with us

  1. Next payment
    95 days from today
    4th payment, tax year 2026 Covers income Sep 1 to Dec 31
  2. 1st payment, tax year 2027. Covers income Jan 1 to Mar 31 185 days from today
  3. 2nd payment, tax year 2027. Covers income Apr 1 to May 31 246 days from today
  4. 3rd payment, tax year 2027. Covers income Jun 1 to Aug 31 338 days from today

For individuals and sole proprietors. A date that falls on a weekend or a legal holiday moves to the next business day.

Federal and Washington business returns, with every estimated payment calculated and sent to you ten days before it is due.

Call (206) 555-0148 See the full year
The next twelve months. Each marker is a typical federal estimated tax date; yellow is next.

Every date runs on the same clock.

We work backward from the due date, so each payment is decided well before it is urgent.

  1. −30 days out

    Check-in

    We ask for the latest books and a note on anything unusual: a big sale, a new hire, a large purchase.

  2. −14 days out

    Projection

    We project the year and test the safe-harbor rules, so you see the minimum payment and the amount that tracks your real income.

  3. −10 days out

    The number

    One message with the amount, the date and how to pay it. Nothing to hunt for.

  4. 0 due date

    Paid and recorded

    The payment posts, we save the confirmation and your calendar rolls forward.

What we handle, on one calendar.

  1. Small business tax

    Federal and Washington returns for sole proprietors, LLCs, S corporations and partnerships, with each estimated payment calculated before it is due.

    Quarterly and yearly

  2. Owner tax returns

    The personal return that sits on top of the business: wages, pass-through income, rentals and investments, filed together.

    Yearly

  3. Entity choice

    A written comparison of how the business is taxed now and how it would be taxed as an LLC, an S corporation or a partnership.

    One-time

  4. Tax notices

    Send us the letter. We read it, tell you what it says and what, if anything, is due.

    As they arrive

  5. Bookkeeping cleanup

    Catch up missed months, sort uncategorized transactions and reconcile the accounts, ready for the return.

    One-time, then monthly

Two CPAs, and you know which one is yours.

  • Dana Whitcomb

    Founding Partner, CPA

    Dana started Northline in 2017 after nine years in public accounting, most of them with owner-managed companies. She leads small business tax, entity choice and notice response.

  • Marcus Oyelaran

    Partner, CPA

    Marcus joined Northline in 2020. He leads owner tax returns, bookkeeping cleanup and the monthly payment-planning plan.

Open weekdays, plus Saturdays in busy season.

Weekdays
Monday to Friday, 9:00 AM to 5:00 PM
Busy season
Busy season, February 1 to April 15: open Saturdays 9:00 AM to 1:00 PM by appointment. Replies may take up to two business days.

Questions owners ask

Which estimated tax dates apply to me?

The board shows the four dates for individuals, which covers sole proprietors, single-member LLC owners, and partners and S corporation shareholders who owe estimated tax on their share of income. A calendar-year C corporation pays on April 15, June 15, September 15 and December 15. Fiscal-year businesses follow other dates. Confirm yours with us.

What happens if I miss an estimated payment?

The IRS charges an underpayment penalty, figured separately for each payment on the amount that was short and the number of days it was short. We calculate it and tell you the number before you file.

Do you work with businesses outside Seattle?

Yes. We work with owners across Washington. Federal returns do not depend on where you live, and we file Washington state business returns with the Department of Revenue.

How do you charge?

A flat fee per return and a fixed monthly fee for payment planning, quoted in writing before work starts.

What should I bring to a first meeting?

Last year's return, this year's profit and loss to date, and any notices from the IRS or the Department of Revenue. If you do not have a profit and loss, bring bank statements and we will build one.

Talk to Northline Tax Advisors

(206) 555-0148
Contact page Email us
Office
2200 Example Avenue, Suite 310, Seattle, WA 98121
Replies
We reply within one business day, and within two in busy season.
Hours
Mon to Fri, 9:00 AM to 5:00 PM. Busy season, February 1 to April 15: open Saturdays 9:00 AM to 1:00 PM by appointment. Replies may take up to two business days.