CMS Medicare DRG Grouper

Centers for Medicare & Medicaid Services · Health

Health No Auth Free & Open Healthcare Insurance DRG Medicare Inpatient

CMS MS-DRG (Medicare Severity Diagnosis Related Groups) grouper assigns DRG codes based on ICD-10-CM diagnoses and ICD-10-PCS procedures. Essential for inpatient hospital reimbursement calculations, case mix index, and hospital billing.

Authentication

No authentication requiredFree to use with no key needed.

Sample Requests

GET CMS IPPS DRG data

Query CMS Inpatient Prospective Payment System DRG data

https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps?limit=10&offset=0

Hover any highlighted part to learn what it does

curl -X GET "https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps?limit=10&offset=0"

import requests
params = {
    "limit": "10",
    "offset": "0"
}
response = requests.get(
    "https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps",
    params=params,
)
print(response.json())

const url = new URL('https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps');
url.searchParams.set('limit', '10');
url.searchParams.set('offset', '0');

const response = await fetch(url); 
const data = await response.json();
console.log(data);

package main

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
)

func main() {
	baseURL, _ := url.Parse("https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps")
	q := baseURL.Query()
	q.Set("limit", "10")
	q.Set("offset", "0")
	baseURL.RawQuery = q.Encode()
	targetURL := baseURL.String()
	req, _ := http.NewRequest("GET", targetURL, nil)

	client := &http.Client{}
	resp, _ := client.Do(req)
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	fmt.Println(string(body))
}

require "net/http"
require "json"

uri = URI("https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps")
uri.query = URI.encode_www_form({
  "limit" => "10",
  "offset" => "0"
})

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == "https"

req = Net::HTTP::Get.new(uri)

res = http.request(req)
puts JSON.parse(res.body)

<?php
$url = "https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps?" . http_build_query([
    "limit" => "10",
    "offset" => "0"
]);
$opts = ["http" => [
    "method" => "GET",
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));

Postman Setup Guide

Get Postman ↗

No authentication required — public CMS software download
Download the MS-DRG Grouper software from https://www.cms.gov (free for non-commercial use)
For web-based grouping, use the 3M or Optum encoder APIs (paid) that implement the CMS logic
The CMS FY2025 definition manual lists all valid DRG codes with relative weights
DRG lookup via IPPS API: GET https://data.cms.gov/api/1/datastore/query/ipps-drg

What can you build with CMS Medicare DRG Grouper?

CMS Medicare DRG Grouper is a Health API. Developers commonly use health APIs for:

accessing medical reference data and drug information
building patient-facing health tracking apps
integrating with EHR and telemedicine platforms
looking up ICD codes and clinical terminology
powering wellness and fitness applications

No authentication required. This API is open — no signup or key needed. Ideal for quick prototypes and public-facing features. CMS Medicare DRG Grouper is free to use, making it a low-risk choice to experiment with.

New to APIs? Read our beginner's guide · Learn about API keys · What is REST?

Open documentation ↗