Free trilingual (EN/ZH/ES) tax calculator covering US federal + all 50 states. New: compare 2025/2026/2027 side by side, save scenarios like W-2 vs freelance to compare line by line, and a self-monitoring freshness alert warns you if the data ever goes stale. Accurate SE tax and short/long-term capital gains. No signup. Interactive step-by-step tutorials, 21 original guides, and FAQ.