Section 179 Deduction Calculator

section-179-deduction-calculator-mcp

An MCP server that calculates the Section 179 deduction, bonus depreciation, heavy SUV and passenger auto limits, and asset loan payments with after-tax cost, using the 2025 and 2026 IRS limits after the One Big Beautiful Bill Act (P.L. 119-21).

Hosted endpoint, no sign-in and no token:

https://section-179-deduction-calculator-mcp.lipmichal.workers.dev/mcp

Tools

Tool	What it does
calculate_section_179	Section 179 deduction with the $2,500,000 (2025) and $2,560,000 (2026) limits, the dollar-for-dollar phase-out above $4,000,000 / $4,090,000, the business income limit and the carryover.
calculate_bonus_depreciation	Bonus depreciation rate from the acquisition and placed-in-service dates: 100% for property acquired after January 19, 2025, the 40% / 60% election, and the phase-down for property acquired earlier. Applies it after Section 179.
get_vehicle_depreciation_limits	First-year limits by gross vehicle weight: passenger auto caps ($20,300 with bonus for 2026), heavy SUV Section 179 cap ($31,300 / $32,000), no cap over 14,000 lb, and the over-50% business use rule.
calculate_asset_loan_payment	Monthly payment, total and first-year interest for an equipment, truck, tractor, RV, land, manufactured home, ATV, pontoon or other asset loan, plus first-year net cash and lifetime after-tax cost for business use.

Every result has structured JSON, a plain-English summary, as_of, source (the irs.gov document) and more (a calculator page on assetloancalculator.com).

What it knows that your model does not

• The One Big Beautiful Bill Act raised the Section 179 limit to $2,500,000 for 2025. Rev. Proc. 2025-32 set $2,560,000 and a $4,090,000 phase-out start for 2026.
• Bonus depreciation is 100% again, permanently, for property acquired after January 19, 2025. The acquisition date is the date of a written binding contract, not delivery.
• Property acquired on or before January 19, 2025 and placed in service in 2025 gets 40%, not 100% (60% for long production property).
• In the first tax year ending after January 19, 2025 you can elect 40% instead of 100%.
• The 2026 heavy SUV cap is $32,000, and the 2026 first-year cap on a car of 6,000 lb or less is $20,300 with bonus (Rev. Proc. 2026-15).
• The IRS has not published the 2027 limits yet (checked 2026-11-02). The tools say so instead of guessing.

Install

Claude.ai custom connector or ChatGPT developer mode

Add a custom connector and paste the URL. No token is needed.

https://section-179-deduction-calculator-mcp.lipmichal.workers.dev/mcp

Claude Code

claude mcp add --transport http section-179-deduction https://section-179-deduction-calculator-mcp.lipmichal.workers.dev/mcp

Or run it locally:

claude mcp add section-179-deduction -- npx -y github:theluckystrike/section-179-deduction-calculator-mcp

Claude Desktop

Add this to claude_desktop_config.json:

{
  "mcpServers": {
    "section-179-deduction": {
      "command": "npx",
      "args": ["-y", "github:theluckystrike/section-179-deduction-calculator-mcp"]
    }
  }
}

Cursor

Add this to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "section-179-deduction": {
      "url": "https://section-179-deduction-calculator-mcp.lipmichal.workers.dev/mcp"
    }
  }
}

VS Code

Add this to .vscode/mcp.json:

{
  "servers": {
    "section-179-deduction": {
      "type": "http",
      "url": "https://section-179-deduction-calculator-mcp.lipmichal.workers.dev/mcp"
    }
  }
}

Node 20 or newer is needed for the local npx version.

Example prompts

• "We placed $4.19 million of equipment in service in 2026. What is our Section 179 limit?"
• "I signed the contract for a CNC machine in December 2024 and it arrived in March 2025. Do I get 100% bonus depreciation?"
• "Can I write off a 6,500 lb SUV that costs $80,000 and that I use 90% for business in 2026?"
• "What is the first-year depreciation cap on a 4,500 lb sedan placed in service in 2026?"
• "I am financing a $120,000 excavator with $20,000 down at 6% for 60 months. What is the payment and the after-tax cost at a 30% rate?"

Data sources

All limits come from irs.gov documents fetched on 2026-11-02: Rev. Proc. 2025-32, the 2025 Instructions for Form 4562, Pub. 946 (2025), Notice 2026-11, Rev. Proc. 2025-16 and Rev. Proc. 2026-15. See DATA_SOURCES.md for each item and URL.

Limitations

• Results are estimates, not tax advice.
• Federal rules only. Many states do not follow Section 179 or bonus depreciation.
• It does not decide whether an asset is qualified property or compute MACRS tables after year one.
• The after-tax cost uses one flat marginal rate and ignores recapture when you sell.
• Qualified production property (IRC 168(n)) and specified plants are not covered.
• Personal tax breaks such as the car loan interest deduction are in a separate server: car-loan-interest-deduction-calculator-mcp.

More

Calculators for people: assetloancalculator.com.

Part of the Zovo MCP collection: https://mcp.zovo.one

Development

npm install
npm run build
npm test

src/core.ts holds all the rules and has no I/O. src/stdio.ts is the local entry and src/worker.ts is the Cloudflare Worker entry. Both use the same tool registry in src/tools.ts.

License

MIT

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The paid back-office collection (invoices, VAT, PDFs, spreadsheets) is at https://mcp.zovo.one