eGFR CKD-EPI 2009 calculator
Estimated glomerular filtration rate is the screening number clinicians, researchers, and product teams use when they need a quick read on how well the kidneys clear waste from blood.
Run — free
This calculator implements the original CKD-EPI 2009 creatinine equation published by Levey and colleagues: enter serum creatinine in mg/dL, age in whole years, and sex, and receive eGFR in mL/min/1.73 m² plus a KDIGO-style GFR category label. The 2009 coefficients (141, sex-specific kappa and alpha, power −1.209, and 0.993 raised to age) differ from the race-free 2021 refit used in many modern labs, so this tool is ideal when you must reproduce historical charts, compare study arms coded with the older formula, or document what a legacy EHR would have reported. The math is fully deterministic and runs locally—no models, labs, or network calls—so the same inputs always produce the same result and patient-like values never leave the request path. This is a screening estimate, not a diagnosis: use it for education, research coding, and product prototypes that need a transparent, auditable eGFR step, and always pair the output with clinician judgment before any care decision.
How to use it
Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.
Check your inputs
Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.
Use it again or automate it
Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.
What you can do with it
Get an answer now
Enter one set of values and see the result without building a spreadsheet or script.
Compare scenarios
Change one value at a time and rerun the calculation to understand what affects the result.
Automate repeated work
Use the API when the same calculation needs to run inside your product or workflow.
FAQ
Which eGFR equation does this calculator use?
The CKD-EPI 2009 creatinine equation (Levey et al., Annals of Internal Medicine 2009). Results are in mL/min/1.73 m² and rounded to one decimal place. The race coefficient from the original paper is not applied.
How does this differ from the CKD-EPI 2021 calculator?
Coefficients differ: 2009 uses base 141, power −1.209, age factor 0.993, and female factor 1.018 with older kappa/alpha pairs. The 2021 race-free equation uses base 142, power −1.200, age factor 0.9938, and female factor 1.012. Use 2009 for historical replication; prefer 2021 for new clinical screening.
What units should I use for serum creatinine?
Milligrams per deciliter (mg/dL). If your lab reports µmol/L, divide by 88.4 to convert to mg/dL before calling the tool.
What happens if creatinine, age, or sex is missing?
The call fails with invalid_input and a message naming the missing or invalid field. Required inputs are positive creatinine in mg/dL, whole-year age 18–120, and sex male or female.
Can I use this result to make a clinical decision?
No. This is a screening estimate for education, research coding, and product prototypes. Diagnosis, drug dosing, and care decisions require a licensed clinician and the full clinical picture.
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/health/egfr-ckd-epi-2009 \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"creatinine":1,"age":50,"sex":"female"}'const res = await fetch("https://api.kit.forhosting.com/health/egfr-ckd-epi-2009", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"creatinine": 1,
"age": 50,
"sex": "female"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/health/egfr-ckd-epi-2009",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"creatinine": 1,
"age": 50,
"sex": "female"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/egfr-ckd-epi-2009", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"creatinine":1,"age":50,"sex":"female"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"creatinine":1,"age":50,"sex":"female"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/egfr-ckd-epi-2009", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"creatinine": 1,
"age": 50,
"sex": "female"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "health.egfr_ckd_epi_2009",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |