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 Maryland 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 Maryland adds
A state layer on top of the federal one. Because the brackets are graduated, your last dollars of freelance profit can be taxed at a higher rate than your first, so a strong year raises your marginal rate as well as your total bill. Most states begin from a federal income figure, which means the deductions that lower your federal tax generally lower your state tax too.
Maryland has state brackets plus a county income tax, so two freelancers with identical income can owe different amounts depending on county.
Quarterly payments in Maryland
Most states that levy an income tax also expect estimated payments through the year from people whose income isn't withheld, and Maryland 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 Maryland 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 Maryland 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.