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mcp-server-calculator

MCP.Pizza Chef: githejie

One tool ships and it does one job: you hand over a written sum and it returns the answer worked out properly rather than guessed. Powers, roots, logarithms, trigonometry, factorials and the usual constants all work, and a caret is accepted for powers. Whole-number arithmetic comes back exact; decimals carry the same rounding any spreadsheet shows. Nothing leaves your computer, and there is no account, key or charge. The code has not changed since May 2025, though a calculator has little that needs changing.

Unmaintained · no code changes since May 2025
Data

Use This MCP server To

Add up a long column of figures without arithmetic slips Work out the percentage change between two numbers Check a compound interest sum before I commit Get a square root, logarithm or factorial instantly Re-run a spreadsheet formula to confirm the total

README

Calculator MCP Server

A Model Context Protocol server for calculating. This server enables LLMs to use calculator for precise numerical calculations.

Available Tools

  • calculate - Calculates/evaluates the given expression.
    • expression (string, required): Expression to be calculated

Installation

Using uv (recommended)

When using uv no specific installation is needed. We will use uvx to directly run mcp-server-calculator.

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

Using PIP

Alternatively you can install mcp-server-calculator via pip:

pip install mcp-server-calculator

After installation, you can run it as a script using:

python -m mcp_server_calculator

Configuration

Using uv (recommended)

Add this to your MCP client settings:

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

Using PIP

Alternatively add this to your MCP client settings:

"mcpServers": {
  "calculator": {
    "command": "python",
    "args": ["-m", "mcp_server_calculator"]
  }
}

License

mcp-server-calculator is licensed under the MIT License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the MIT License. For more details, please see the LICENSE file in the project repository.

mcp-server-calculator FAQ

Is it still maintained?
The last change was May 2025, so it has been quiet for over a year. It is about sixty lines of code doing one job, so there is little to go stale.
Do I need a key or an account?
No. It runs entirely on your own machine, reaches nothing on the internet, and costs nothing.
Which apps does it work in?
Any assistant that lets you paste a small tool-server entry into its settings. The project does not name particular apps, and it does not need to.
Can I use this to double-check my spreadsheet totals?
Yes. Paste the numbers or the formula into the chat and ask for the result; the sum is computed rather than estimated by the model.
Is it genuinely precise?
For whole numbers, yes, however large. Decimals use ordinary computer rounding, so 0.1 plus 0.2 comes back as 0.30000000000000004, exactly as a spreadsheet would compute it.
Can it run anything other than maths?
No, and that is deliberate. Only arithmetic and a fixed list of standard maths functions are permitted; anything else is refused outright. It cannot read your files or reach the network.
Does it handle currency conversion, units or dates?
No. It evaluates a plain numeric expression and nothing more, so exchange rates and unit conversions have to come from elsewhere.