The shock of the first freelance tax bill
Employees never see the employer half of payroll taxes. The self-employed pay both halves, all at once, on top of income tax — which is why a freelancer earning the same headline figure as an employee keeps meaningfully less unless they plan for it. On $98,000 of net business income, self-employment tax alone is roughly $13,800 before a dollar of income tax.
Deductions are the main lever
Self-employment tax is charged on net earnings, so every legitimate business expense reduces both income tax and the 15.3%. Commonly missed deductions include the home office (simplified method: a fixed rate per square foot), business mileage, health insurance premiums, professional development, software and subscriptions, and the business portion of a phone or internet bill. Keep records; the standard for substantiation is contemporaneous, not reconstructed.
Retirement accounts do double duty
A SEP-IRA or Solo 401(k) allows contributions far above an IRA limit, and reduces taxable income directly. A Solo 401(k) is usually more generous at moderate income because it allows both an employee deferral and an employer profit-sharing contribution, and it permits Roth deferrals.
The S-corp question
Above roughly $80,000–$100,000 of net profit, electing S-corporation status can reduce self-employment tax by splitting income between a reasonable salary (subject to payroll tax) and distributions (not subject to it). The trade-off is payroll administration, a separate return and accounting fees of $1,500–$3,000 a year. Model it properly with an accountant before electing — and note that "reasonable salary" is a real requirement, not a formality.
Systems that prevent the January panic
Open a separate tax savings account and transfer a fixed percentage of every payment on the day it arrives. Pay quarterly estimates on time. Reconcile monthly rather than annually. The failure mode for freelancers is almost never ignorance of the rules; it is spending money that was never theirs.
This is an estimate. Tax rules change and depend on your circumstances — confirm with a qualified tax professional.