StructureCost2026

Quarterly estimated tax in Washington (2026)

A sole proprietor in Washington with $100,000 of profit pays the IRS about $4,878 a quarter. Put in your own profit to get the four payments and their dates.

$4,878 a quarter

to the IRS. Four payments make $19,512 for the year, which meets 90% of this year's tax. This year's federal tax on this profit: $21,679 (income tax $7,867, self-employment tax $13,812).

Washington, 2026: $100,000 profit, single filer

IRS dueIncome earnedIRS
April 15, 2026January 1 to March 31$4,878
June 15, 2026April 1 to May 31$4,878
September 15, 2026June 1 to August 31$4,878
January 15, 2027September 1 to December 31$4,878
Year$19,512

Washington has no personal income tax, so only the IRS payments apply. Estimates assume a single-member business with no withholding.

Washington estimated tax rules for 2026

Payments at each profit

ProfitIRS each quarterWashington for the year
$50,000$2,190$0
$100,000$4,878$0
$150,000$8,230$0
$250,000$14,450$0
$500,000$37,380$0

A sole proprietor or single-member LLC, single filer, no withholding, paying 90% of this year's federal tax.

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