TaxNinja is a free tax calculator built specifically for US freelancers and 1099 workers. Enter your income, answer 10 questions about your work situation, and get your estimated tax bill — with every IRS Schedule C deduction you qualify for. No account. No signup. Your numbers never leave your browser. Covers 30+ deduction categories including home office, mileage, equipment, retirement contributions, and health insurance. Uses official 2026 IRS tax rates.