MCP server: One MCP server.

Kalkulatory Place

@grynienmMCP server · External

Polish payroll: gross↔net salary, hourly rates, tax brackets and ZUS rates from a live public API

Payrollv1.0.2MITJavaScript
Freeno charge per call

Runs on your machine from its package; the steps are below.

What it does

  1. Reads
  2. Writes
  3. High impact

Not assessed yet.

What it costs

Free

Odel charges nothing per call. The publisher may charge for its own service.

Runs locally over stdio

This server isn't hosted — your MCP client launches it from a package registry. Use one of the commands below, or drop the config into your client (e.g. Claude Desktop).

npm@kalkulatory-place/mcpv1.0.2

Run

npx -y @kalkulatory-place/mcp

MCP client config

{
  "mcpServers": {
    "kalkulatory-place": {
      "command": "npx",
      "args": [
        "-y",
        "@kalkulatory-place/mcp"
      ]
    }
  }
}
README3 min read

Kalkulatory Płace — MCP server

npm license test

Polish payroll for AI assistants. Five MCP tools that turn "how much do I take home from 11 600 PLN gross?" from a guess into an answer that matches the actual bank transfer to the cent.

Ask a model this today and it computes from memory. Polish PIT and ZUS rates change every year, the income-tax advance rounds to whole złoty, the health contribution has a statutory cap, and the answer is quietly wrong. This server hands the model a precomputed answer from the same engine that renders kalkulatory-place.pl, so the number in the chat and the number on the linked page are identical.

No API key. No rate limits. No npm dependencies.

Install

bash
claude mcp add kalkulatory-place -- npx -y @kalkulatory-place/mcp

Any other MCP client (claude_desktop_config.json and friends):

json
{
  "mcpServers": {
    "kalkulatory-place": {
      "command": "npx",
      "args": ["-y", "@kalkulatory-place/mcp"]
    }
  }
}

Tools

ToolAnswers
brutto_na_nettoNet pay from a gross amount — employment contract (itemised ZUS, health, PIT advance), civil-law contracts, employer cost, under-26 exemption, yearly totals
netto_na_bruttoThe gross salary needed to take home a given net amount
stawka_godzinowaNet from an hourly gross rate — civil-law contract and employment
stawki_rokuMinimum wage, tax-free allowance, PIT brackets, ZUS rates, 30× cap for a given year
katalogSupported years, amount ranges, API URL patterns

Every response carries stanPrawnyNa (the date the law was checked), statusRocznika (final or projekt — the year's rates are still a draft bill) and zrodlo, a URL to the full human-readable breakdown.

How it works

A thin client over a static JSON API: plain GETs off a CDN, no key, no limits.

MCP client ──stdio JSON-RPC──▶ this server ──HTTPS GET──▶ /api/v1/…json (CDN)

Why a thin client and not a copy of the engine. The numbers must be identical to what the user sees after clicking zrodlo. A server doing its own maths would silently drift apart the first time rates changed upstream — and the drift would be noticed by whoever was shown the wrong number.

Why no dependencies. MCP is handled directly as newline-framed JSON-RPC 2.0 over stdio. A package with no dependencies starts under npx in about a second and cannot break when somebody else's SDK updates under a server everyone has forgotten about.

The underlying API is public and documented in OpenAPI 3.1: https://kalkulatory-place.pl/openapi.json. There is also an llms.txt.

Configuration

VariableDefaultPurpose
KALKULATORY_APIhttps://kalkulatory-place.plBase URL — point it at a local build for testing

Test

bash
npm test

Runs a real handshake against the published server: initialize, tools/list, then a brutto_na_netto call, and checks the result against the published net figure.

License

Code: MIT. Data and calculations: CC BY 4.0 — when quoting a number, cite the URL from zrodlo. See NOTICE.

This is not tax advice. Figures are informational.


Po polsku

Serwer MCP do liczenia polskich wynagrodzeń. Daje asystentowi AI pięć narzędzi zamiast zgadywania stawek PIT i ZUS z pamięci.

Odpowiedzi pochodzą z kalkulatory-place.pl — z tego samego silnika, który renderuje strony serwisu, więc liczba w czacie zgadza się co do grosza z tym, co użytkownik zobaczy po kliknięciu w link źródłowy.

NarzędzieOdpowiada na
brutto_na_nettoIle netto z X zł brutto — etat (z rozbiciem na składki), zlecenie, dzieło, koszt pracodawcy, ulga do 26 lat, sumy roczne
netto_na_bruttoJakie brutto daje X zł netto na etacie
stawka_godzinowaIle netto ze stawki X zł/h — zlecenie i etat
stawki_rokuPłaca minimalna, kwota wolna, progi PIT, stopy składek ZUS, limit 30-krotności
katalogObsługiwane roczniki i zakresy kwot

Każda odpowiedź niesie stanPrawnyNa, statusRocznika (final albo projekt — rocznik jeszcze nieuchwalony) oraz zrodlo, czyli adres strony z pełnym rozbiciem dla człowieka.

Instalacja bez klucza API i bez zależności:

bash
claude mcp add kalkulatory-place -- npx -y @kalkulatory-place/mcp

Wydawca: Bril Brothers Innovation Labs sp. z o.o., KRS 0001262781. Serwis nie jest doradcą podatkowym; wyliczenia mają charakter informacyjny.

Similar modules

Browse Payroll