Kalkulatory Place

io.github.grynienMv1.0.2Updated Oct 7, 2026

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

VerifiedSTDIODesktop onlyData & AnalyticsFinance

Overview

AI-generated overview

Lets an assistant compute Polish payroll figures — gross-to-net salary, hourly rates, and yearly PIT and ZUS rates — from a public API.

What it does
Five tools cover Polish payroll calculations: net pay from a gross amount (employment and civil-law contracts, itemised ZUS and health contributions, PIT advance, employer cost, under-26 relief, yearly totals), the gross needed for a target net, net from an hourly gross rate, and the statutory rates for a given year (minimum wage, tax-free allowance, PIT brackets, ZUS rates, the 30× cap). A catalogue tool lists supported years, amount ranges and API URL patterns. Each response includes the date the law was checked, whether the year's rates are final or still a draft bill, and a link to a human-readable breakdown.
When to use it
Useful when an assistant has to answer Polish salary questions where memorised PIT and ZUS rates would be wrong or out of date, for example take-home pay from a gross offer or the gross needed for a target net. It is a calculation aid, not tax advice.
Requirements
Runs locally over stdio via npx from the npm package @kalkulatory-place/mcp; Node.js and network access to the public API are needed. No API key or account. An optional KALKULATORY_API variable overrides the base URL, for example to point at a local build.
Before you install
Calculations are informational and the service states it is not a tax adviser; results depend on the year's rates, which may still be a draft bill. The server sends the amounts you ask about to a third-party public API over HTTPS. No credentials, payments or write actions are involved.

Installation

In SourceWeft

  1. Open Kalkulatory Place in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

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.

Source: README.md at commit 0ce8672

Tools

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Version history

1
  1. v1.0.2LatestOct 7, 2026