Axiom Calculator MCP

Personal finance calculators for Claude and AI agents — mortgage payments, compound interest, FIRE retirement number, loan comparison, debt payoff, and inflation-adjusted returns.

Zero API keys. Zero setup. Works instantly with any MCP client.

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Tools (8 total)

Tool	What it does
mortgage_calculator	Monthly payment, total interest, 12-month amortization schedule
rent_vs_buy	Compare total cost of renting vs buying over N years (includes equity, appreciation, opportunity cost)
compound_interest	Project investment growth with optional monthly contributions — year-by-year table
fire_number	Calculate your FIRE target portfolio and years-to-retirement timeline
inflation_adjusted_return	Real vs nominal return — see if your investments actually beat inflation
loan_comparison	Compare two loans by total cost, monthly payment, and true APR (including fees)
true_credit_cost	Find the real APR of any financing offer, BNPL, or credit product
debt_payoff_plan	Payoff timeline and interest saved from extra monthly payments

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Install

Claude Desktop / Claude Code

Add to your MCP config:

{
  "mcpServers": {
    "calculator": {
      "command": "uvx",
      "args": ["axiom-calculator-mcp"]
    }
  }
}

Any MCP client (stdio)

uvx axiom-calculator-mcp

From source

git clone https://github.com/vdalhambra/axiom-calculator-mcp
cd axiom-calculator-mcp
uv run axiom-calculator

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Example usage

Once connected, just ask Claude naturally:

"I'm looking at a $450,000 house with 20% down at 6.8% for 30 years. What's my monthly payment and total interest?"

"Compare a 15-year loan at 6.2% vs 30-year at 6.8% for $380,000. Which is better overall?"

"I spend $48,000/year. How much do I need to retire, and how long will it take if I save $24,000/year?"

"I have $8,500 in credit card debt at 22% APR. How long to pay it off at $250/month, and how much do I save if I add $100/month extra?"

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Why this exists

Most finance calculators are either locked behind paywalls, require accounts, or are ad-stuffed websites. This MCP gives Claude direct access to accurate financial math — no API keys, no rate limits, no middleman.

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Part of the Axiom MCP suite

• FinanceKit MCP — Stock quotes, fundamentals, crypto, insider transactions
• SiteAudit MCP — SEO audits, Core Web Vitals, backlink analysis

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License

MIT — free to use, modify, and distribute.