MCP Calculator

A modern Model Context Protocol server for mathematical calculations. Exposes 13 tools (6 core + 7 specialized) with high-precision arithmetic, a safe expression evaluator, statistics, unit conversion, and financial math.

Requirements

• Python 3.10+
• uv (or Docker, for the containerized setup)

Installation

uv venv

uv pip install -e ".[dev]"

Running

The server supports two transports, selected via the MCP_TRANSPORT environment variable (see Configuration).

STDIO

The server speaks MCP over stdio by default (the transport used by most MCP clients such as Claude Desktop and Claude Code):

source .venv/bin/activate

mcp-calculator

Streamable HTTP

To serve over streamable HTTP instead:

source .venv/bin/activate

MCP_TRANSPORT=http mcp-calculator

The HTTP endpoint is then available at http://0.0.0.0:8080/mcp/.

Docker

Build the image and run it in HTTP mode (the image defaults to HTTP on port 8080):

docker build -t mcp-calculator .

docker run --rm -p 8080:8080 mcp-calculator

Override any setting at runtime with -e, e.g. a different port:

docker run --rm -p 9000:9000 -e MCP_PORT=9000 mcp-calculator

Configuration

Variable	Default	Description
MCP_TRANSPORT	stdio	Transport to use: stdio or http (streamable HTTP).
MCP_HOST	0.0.0.0	Host/interface to bind when using HTTP. Use 0.0.0.0 to expose it.
MCP_PORT	8080	Port to listen on when using HTTP.

Available Tools

Core

Tool	Description
basic_math	add / subtract / multiply / divide with decimal precision (0-15)
advanced_math	trig, inverse trig, log/ln, sqrt, abs, factorial, exp, pow
expression_eval	evaluate expressions with variables, constants, and functions
statistics_analysis	mean, median, mode, std_dev, variance, percentile, range, skewness, kurtosis, summary
unit_conversion	length, weight, temperature, volume, area
financial_calc	simple/compound interest, loan payment, ROI, present/future value

Specialized

Tool	Description
stats_summary	full statistical overview of a dataset
percentile	a specific percentile (0-100) of a dataset
batch_conversion	convert many values between units at once
npv	Net Present Value of cash flows
irr	Internal Rate of Return (Newton-Raphson)
loan_comparison	compare loans, return the lowest monthly payment
investment_scenarios	compare investments, return the highest return

Development

Testing

Run the test suite with:

pytest

License

MIT