MCP Calculator Server: Fix LLM Math Once and For All

Stop watching your LLM botch basic arithmetic. You know the drill - ask Claude to calculate 847 * 23 + 156 and get three different "close enough" answers. When you're building data analysis workflows, financial models, or any application where precision matters, LLM math approximations don't cut it.

The Real Problem with LLM Math

LLMs don't calculate - they approximate based on training patterns. That's fine for creative writing, terrible for your expense report calculations or data transformations. You end up constantly double-checking numbers, breaking flow to verify calculations externally, or worse - shipping inaccurate results.

This MCP server gives your LLM access to a proper calculator that returns exact results every time.

What You Get

Precise Calculation Tool: A single calculate tool that evaluates mathematical expressions with full precision. No more "approximately 19,481" - you get exactly 19,481.

Zero Friction Integration: Add one JSON configuration block to your MCP client and you're done. No complex setup, no API keys, no external dependencies.

Expression Flexibility: Handles everything from basic arithmetic to complex expressions with parentheses, powers, and nested operations.

Real-World Impact

Data Analysis Workflows: Process CSV files, calculate aggregations, transform datasets - all with confidence in your numbers.

Financial Applications: Build expense trackers, budget calculators, or investment analysis tools without worrying about calculation drift.

Engineering Calculations: Convert units, calculate loads, verify measurements - get the precision you need for technical work.

Research and Reporting: Generate accurate statistical summaries, calculate percentages, perform data transformations for reports.

Quick Setup

Install with uv (recommended):

curl -LsSf https://astral.sh/uv/install.sh | sh

Add to your MCP client configuration:

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

That's it. Your LLM now has access to precise calculations.

Why This Matters

You're building applications that depend on accurate data. Every time your LLM approximates instead of calculates, you introduce potential errors that compound through your workflow. This server eliminates that uncertainty with a simple, reliable calculation tool that integrates seamlessly into your existing MCP setup.

Perfect for developers who need their AI assistants to handle numbers correctly the first time, every time.