The federal part applies everywhere
Wherever you live, self-employment income carries two federal taxes. The first is self-employment tax at 15.3% of net earnings, covering Social Security and Medicare — the portions an employer would normally split with you. The second is federal income tax, calculated on your profit after the standard deduction and the deductible half of your self-employment tax.
This part does not change based on your state. A freelancer in Ohio and a freelancer anywhere else owe the same federal self-employment tax on the same profit. The self-employment tax calculator works out that figure.
What Ohio adds
A state layer on top of the federal one. Because the rate is flat, your state liability scales directly with your taxable income: the same percentage applies whether you had a strong year or a lean one, which makes estimating it straightforward once you know the rate. Most states begin from a federal income figure, which means the deductions that lower your federal tax generally lower your state tax too.
Ohio moved to a flat rate on nonbusiness income above a threshold, and many Ohio municipalities levy their own local income tax.
Quarterly payments in Ohio
Most states that levy an income tax also expect estimated payments through the year from people whose income isn't withheld, and Ohio generally follows that pattern. That means two sets of quarterly payments: one to the IRS and one to the state, on their own schedule and through their own payment system. Confirm the current thresholds and due dates with the Ohio department of revenue, since state deadlines don't always line up with the federal ones.
The quarterly estimated tax calculator handles the federal side, and the deadlines guide lists the federal due dates.
Deductions work the same way
Business expenses reduce your net profit, which lowers your federal self-employment tax and federal income tax and generally your Ohio state tax as well, since most states start from a federal income figure. Software, equipment, a home office, mileage, and professional fees commonly qualify. The write-off guide covers what usually counts.