Everyday calculator MCP server (stdio): 15 core tools, full macalc catalog on demand. No API key.
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Docker image of the macalc MCP server: a stdio Model Context Protocol server that gives an AI assistant real calculators instead of mental arithmetic. Free, no API key, no account.
The image is built from the tagged source of the npm package macalc-mcp (same version as the image tag) on
node:22-alpine, for linux/amd64 and linux/arm64, and runs as a non-root user.
In the configuration of your MCP client (Claude Desktop, Cursor, VS Code…):
{
"mcpServers": {
"macalc": {
"command": "docker",
"args": ["run", "-i", "--rm", "tresor4k/macalc-mcp:latest"]
}
}
}
The server talks MCP over stdin/stdout, so -i is required. It forwards each calculation to the public endpoint
https://macalculatriceenligne.com/api/mcp: the container needs outbound HTTPS.
15 tools by default, kept small on purpose so they do not crowd the context window of the assistant:
| Tool | What it does |
|---|---|
calculate_french_income_tax | French income tax (family quotient) |
calculate_french_salary | French gross to net salary |
calculate_us_federal_tax | US federal income tax |
calculate_uk_income_tax | UK income tax |
calculate_canada_federal_tax | Canadian federal income tax |
calculate_mortgage | Monthly payment, total interest, amortization schedule |
calculate_compound_interest | Compound growth with yearly breakdown |
calculate_loan_payment | Amortizing loan |
calculate_percentage | Percent of total, percent change |
calculate_vat_generic | Add or remove VAT, GST or sales tax |
calculate_bmi | Body Mass Index |
calculate_tdee | Maintenance calories |
list_bundles | Thematic bundles of the full catalog |
get_bundle_tools | Tools inside one bundle |
call_any_calculator | Call any calculator of the catalog by name |
The three last tools reach the rest of the catalog (construction, conversions, running, real estate, Belgium, Switzerland, Quebec…). The calculators are the ones published on MaCalculatriceEnLigne, a French site of free online calculators; the HTTP API is documented in the API reference.
| Variable | Effect |
|---|---|
MACALC_MCP_FULL=1 | Expose the full remote catalog instead of the 15 core tools |
MACALC_MCP_URL | Override the endpoint (default https://macalculatriceenligne.com/api/mcp) |
docker run -i --rm -e MACALC_MCP_FULL=1 tresor4k/macalc-mcp:latest
The same server runs with npx -y macalc-mcp, or without any install through the remote endpoint above for clients
that support Streamable HTTP.
The results are an aid to calculation, not tax, legal or medical advice; official texts prevail. Source and issues: https://github.com/tresor4k/macalc-mcp — MIT licence.
Content type
Image
Digest
sha256:9a71468f5…
Size
64.6 MB
Last updated
6 days ago
docker pull tresor4k/macalc-mcp