1099 Tax Calculator, Federal and State: Add the State Row

Quick Answer: A 1099 tax calculator for federal and state tax adds one layer to the federal estimate: your state's income tax on the same net profit. Many states, including Illinois and California, start from federal adjusted gross income, so half of your self-employment tax already reduces the state figure. On $70,000 of 2026 profit, a single filer's state tax runs from $0 in Washington to about $3,079 in Illinois.

Federal self-employment tax and income tax are the same in every state, so the state part is the only piece of a 1099 estimate that depends on where you live. Find your state's type (no wage income tax, flat rate or graduated brackets), its starting line, its deduction or exemption, and its estimated payment schedule, then add one row to your spreadsheet.

Every state figure below was read from the state revenue department's own pages on October 28, 2026. Federal figures come from the IRS 2026 Form 1040-ES. This is an estimate for planning, not a filing.

Why does the state part of a 1099 estimate start from federal AGI?

Most income-tax states don't make you recompute your business profit from scratch. They copy a line from your federal return and adjust it. For self-employed people, which line they copy decides how much of the federal arithmetic carries over.

• Illinois: Form IL-1040 line 1 is "the adjusted gross income from your federal return," per the 2025 IL-1040 instructions.
• California: Form 540 line 13 is federal AGI from Form 1040 line 11b. California's Schedule CA instructions allow the deductible part of self-employment tax unless California treats you as an employee rather than a contractor.

Federal AGI is your net profit minus the deduction for half of self-employment tax (and any other adjustments, such as a SEP contribution). So a state that starts at AGI automatically gives you the half-SE-tax break. What it does not give you are the deductions that come after AGI on the federal return: the federal standard deduction and the qualified business income deduction. Each state replaces those with its own, usually much smaller, deduction or exemption. That is why state taxable income is often higher than federal taxable income for the same person.

Federal starting numbers for the worked example

The example is a single filer with $70,000 of 2026 net profit from 1099 work and no other income. The federal layer, using the 2026 Form 1040-ES worksheets:

If you want those cells built with formulas, the federal self-employed tax spreadsheet walks through each one. The only number the state layer needs from it is AGI: $65,054.66.

What does the same $70,000 cost in three different states?

No wage income tax: Washington

Washington's Department of Revenue says the state "does not currently have an individual income tax." It adds that a new 9.9% tax will apply from January 1, 2028 to individuals and joint filers with annual AGI over $1 million. At $70,000 the state income tax row is zero.

Zero income tax is not zero state tax for a business, though. Washington's business and occupation (B&O) tax is charged on gross receipts, and the department notes that businesses "cannot deduct expenses such as labor, materials, taxes, or other costs." The rate depends on which of more than 50 classifications your work falls under, and a small business credit can reduce it. Check the Washington B&O tax page before you assume your state row is empty.

Flat rate: Illinois

The Illinois Department of Revenue lists a single individual rate of 4.95% of net income. The 2025 exemption allowance is $2,850 per person, and the IL-1040-ES worksheet subtracts only that exemption from base income before applying the rate.

• Illinois base income: $65,054.66 (federal AGI, no Illinois additions or subtractions here)
• Minus exemption: $2,850
• Net income: $62,204.66
• Tax at 4.95%: $3,079.13

Graduated brackets: California

California's latest published rate schedules are for 2025. Its standard deduction for a single filer is $5,706, and each personal exemption is a $153 credit against tax rather than a deduction.

• California AGI: $65,054.66
• Minus standard deduction: $5,706
• Taxable income: $59,348.66
• Tax from the 2025 single schedule: $1,987.41 + 8% of the amount over $57,542 = $2,131.94
• Minus personal exemption credit: $153
• California tax: $1,978.94

California tells filers with taxable income of $100,000 or less to use its tax table instead of the rate schedule, so the table figure may differ by a few dollars.

The three side by side

The graduated state comes out cheaper than the flat one at this income because California's lower brackets and exemption credit outweigh its higher top rates. At higher profit the order reverses: California's single schedule reaches 9.3% above $72,724 of taxable income, while Illinois stays at 4.95%.

Adding a state row to your calculator

Put a lookup table on a tab named States, one row per state you might file in:

For a graduated state, add its bracket table on another tab (CA_Brackets) with the lower bound, base tax and rate, copied from the state's schedule. California's 2025 single schedule starts: 0 / 0 / 1%; 11,079 / 110.79 / 2%; 26,264 / 414.49 / 4%; 41,452 / 1,022.01 / 6%; 57,542 / 1,987.41 / 8%; 72,724 / 3,201.97 / 9.3%, continuing to 12.3% above $742,953.

With federal AGI in Calc!B9 and the state code in Inputs!B8, the state taxable amount and tax are:

• B20 State taxable: =MAX(0,Calc!B9-VLOOKUP(Inputs!B8,States!A2:E4,3,FALSE))
• B21 State tax: =IF(VLOOKUP(Inputs!B8,States!A2:E4,2,FALSE)="none",0,IF(VLOOKUP(Inputs!B8,States!A2:E4,2,FALSE)="flat",B20*VLOOKUP(Inputs!B8,States!A2:E4,4,FALSE),MAX(0,VLOOKUP(B20,CA_Brackets!A2:C10,2,TRUE)+(B20-VLOOKUP(B20,CA_Brackets!A2:A10,1,TRUE))*VLOOKUP(B20,CA_Brackets!A2:C10,3,TRUE)-VLOOKUP(Inputs!B8,States!A2:E4,5,FALSE))))
• B22 Federal plus state: =Calc!B12+B21

The graduated branch points at one bracket tab; if you track more than one graduated state, use INDIRECT(Inputs!B8&"_Brackets!A2:C10") in place of the fixed range. Update the deduction, exemption and brackets each year from the state's new forms; the Illinois and California numbers above are 2025 amounts.

How do state estimated tax payments differ from federal ones?

States collect from the self-employed the same way the IRS does, through quarterly payments, but the thresholds and splits are their own.

For the example, Illinois would be four payments of about $770. California would be about $594 in April, $792 in June, nothing in September and $594 in January. California's uneven split catches people who copy the federal pattern: a quarter of the year's tax in June is too little there. California also says that if you file your 2026 return by January 31, 2027 and pay the balance, you can skip the last installment. Washington has no income tax vouchers; B&O tax is reported on its excise tax return.

Do cities add their own tax on self-employment income?

Some do, and it's easy to miss because it often sits outside the state return. Philadelphia is a clear example. Its Net Profits Tax applies to sole proprietors, partnerships, associations, LLCs, and estates or trusts that run a business, and for tax year 2025 the rate is 3.74% of net profits for residents and 3.43% for non-residents doing business in the city. Estimated payments are due April 15 and June 15, each equal to 25% of the prior year's tax, and the city requires a return even when the business had a loss.

On the example's $70,000, a Philadelphia resident would add roughly $2,618 at the 2025 resident rate, before any credits the city allows. In Washington, the Department of Revenue's B&O page also points to separate city B&O taxes. Check your city and county finance department's site when you set up the calculator; a missing local row is a common reason a 1099 estimate falls short.

Feeding the calculator real numbers

Everything above multiplies from one input, net profit, so a guessed expense total throws off federal tax, state tax and local tax at once. Build profit from your bank and card statements: tag each deposit as business income, each payment as a deductible category or personal, and total the year. QuickBankConvert converts statement PDFs into spreadsheet rows you can tag and total. The quarterly bank statement workflow shows how to refresh the numbers before each payment date, and how much of each 1099 deposit to save turns the combined rate from the table into a set-aside percentage.

Related guides

• Self-employed income tax calculator in Excel
• Employed and self-employed tax calculator (W-2 + 1099)
• How to track estimated tax payments from bank statements