Creatinine clearance calculator
Creatinine clearance is a long-standing bedside estimate of how quickly the kidneys remove creatinine from the blood, expressed in milliliters per minute.
Run — free
Unlike body-surface-area-normalized eGFR, the classic Cockcroft-Gault formula yields an absolute clearance in mL/min that many drug-dosing tables and older clinical pathways still reference. This calculator implements that published equation exactly: enter adult age in years, body weight in kilograms, sex, and serum creatinine in mg/dL, and receive CrCl plus the sex factor applied so every step is auditable. The math is fully deterministic and runs without models, labs, or network calls, so the same inputs always produce the same result and patient-like values never leave the request path. Use it for education, research coding, product prototypes, and transparent screening arithmetic—not as a standalone diagnosis or a substitute for a licensed clinician.
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 equation does this creatinine clearance calculator use?
The classic Cockcroft-Gault formula: CrCl = ((140 − age) × weight_kg × sex_factor) / (72 × Scr_mg/dL), with sex_factor 1.0 for male and 0.85 for female. Results are in mL/min and rounded to one decimal place.
What units should I use for weight and creatinine?
Weight in kilograms and serum creatinine in mg/dL. Convert pounds by dividing by 2.205; convert µmol/L creatinine by dividing by 88.4 before calling the tool.
How is this different from eGFR?
Cockcroft-Gault returns absolute clearance in mL/min and uses weight. Common eGFR equations (for example CKD-EPI) estimate filtration normalized to 1.73 m² BSA and do not take weight the same way. Many drug labels still cite CrCl specifically.
What happens if creatinine or another field is missing?
The call fails with invalid_input and a message naming the field. Missing, non-numeric, or non-positive creatinine values are rejected and are not billed.
Can I use this result to make a clinical decision?
No. This is a screening estimate for education, prototyping, and research, not medical advice. Diagnosis, dosing, and treatment decisions need a licensed clinician reviewing the full clinical picture.
How much does the API cost?
The browser widget runs free and locally. The same computation via the API is billed at $0.002 per successful request from prepaid KIT balance, with no charge on invalid_input failures.
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/creatinine-clearance \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"age":50,"weight":70,"sex":"male","creatinine":1}'const res = await fetch("https://api.kit.forhosting.com/health/creatinine-clearance", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"age": 50,
"weight": 70,
"sex": "male",
"creatinine": 1
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/health/creatinine-clearance",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"age": 50,
"weight": 70,
"sex": "male",
"creatinine": 1
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/creatinine-clearance", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"age":50,"weight":70,"sex":"male","creatinine":1}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"age":50,"weight":70,"sex":"male","creatinine":1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/creatinine-clearance", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"age": 50,
"weight": 70,
"sex": "male",
"creatinine": 1
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "health.creatinine_clearance",
"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. |