Blood pressure category calculator
Adult blood pressure is reported as two numbers in millimetres of mercury: systolic pressure when the heart contracts and diastolic pressure when it relaxes.
Run — free
Runs in your browser. Free, unlimited — your data never leaves this page.
The American College of Cardiology and American Heart Association publish a widely taught adult threshold table that maps those two numbers into five ordered categories—normal, elevated, hypertension stage one, hypertension stage two, and hypertensive crisis—so patients, students, and product teams can label a reading the same way every time. This capability applies that ACC/AHA table deterministically: it validates the pair, rejects impossible orderings where diastolic exceeds systolic, picks the more severe band when the two numbers disagree, and returns structured JSON with a machine-readable category key, a human label, the echoed reading string, and the guideline name. The path is pure comparison logic with no network, no model, and no wall clock, so homework checkers, coaching apps, and prepaid API clients pin identical outputs in tests. The browser widget runs free on your device; the prepaid API charges $0.002 per successful item when servers and SDKs need the same contract.
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
What blood pressure categories does this calculator use?
ACC/AHA 2017 adult categories: normal (SBP < 120 and DBP < 80), elevated (SBP 120–129 and DBP < 80), hypertension stage 1 (SBP 130–139 or DBP 80–89), hypertension stage 2 (SBP ≥ 140 or DBP ≥ 90), and hypertensive crisis (SBP > 180 and/or DBP > 120).
What happens if diastolic exceeds systolic?
The request fails with invalid_input. Diastolic must not be greater than systolic; when it is, the calculator rejects the pair without charging and the error message mentions that diastolic exceeds systolic.
What if systolic and diastolic fall into different stages?
The higher (more severe) category is returned. For example, 125/82 is hypertension stage 1 because diastolic is 80–89, not elevated.
Is the blood pressure category calculator free?
The browser tool runs free on your device. API calls use prepaid KIT balance at $0.002 per successful item; validation failures are not charged.
Is this a medical diagnosis?
No. It is an educational classification of a reading pair under ACC/AHA thresholds. It does not replace clinical assessment, ambulatory monitoring, or professional medical advice.
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/blood-pressure-category \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"systolic":118,"diastolic":76}'const res = await fetch("https://api.kit.forhosting.com/health/blood-pressure-category", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"systolic": 118,
"diastolic": 76
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/health/blood-pressure-category",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"systolic": 118,
"diastolic": 76
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/blood-pressure-category", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"systolic":118,"diastolic":76}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"systolic":118,"diastolic":76}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/blood-pressure-category", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"systolic": 118,
"diastolic": 76
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "health.blood_pressure_category",
"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. |