Quarterly Tax Calculator
免費的美國自僱人士季度預估稅款MCP伺服器。estimateQuarterlyTax根據年度淨利潤、申報身份、州別及稅務年度（2025/2026，支援QBI）計算聯邦及州所得稅、自僱稅，以及四個季度分期款項；getPaymentCalendar回傳四個IRS季度截止日期，並自動順延週末及IRS假日。遠端端點：https://mcp.quarterlytax.al157.xyz/mcp（Streamable HTTP，無需驗證）。唯讀計算；不儲存任何資料。
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文件
Your numbers
Business revenue minus expenses — the profit you report.
State tax is a rough estimate — graduated marginal brackets for CA, NY, NJ, HI and OR; single approximate marginal rate elsewhere.
§199A simplified estimate — assumes a non-SSTB business with no W-2 wages paid. Thresholds follow the selected tax year.
tax-rules: 2026 federal states 2025 Rates verified for tax year 2026 — rates change yearly, IRS figures govern. State estimates: 2025 data.
Federal / quarter
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State / quarter
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Safe harbor comparison
Payment calendar
Pay via IRS Direct Pay ↗ Pay via EFTPS ↗
Due dates follow the IRS rule: a date falling on a weekend or legal holiday moves to the next business day. Always confirm on irs.gov before paying.