ForHosting KIT · Developer Utilities

Gellish max heart rate calculator

Gellish max heart rate calculator: enter your values and see a clear result on this page. Free for individual checks; API from $0.002.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

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 does the Gellish max heart rate calculator cost?

It is free in your browser on this page. Through the API a successful request costs $0.002; invalid inputs are not charged.

What is the Gellish equation for maximum heart rate?

The linear Gellish form is HRmax = 207 − 0.7 × age, with age in years and HRmax in beats per minute. The response field hrmax_bpm holds that estimate.

How is Gellish different from Fox or Tanaka?

Fox is 220 − age. Tanaka is 208 − 0.7 × age. Gellish uses the same 0.7 slope as Tanaka but a 207 intercept, so the two differ by one beat per minute at every age.

What happens if age is missing, zero, or negative?

The input is rejected with invalid_input. Age is required and must be a positive finite number; missing and non-positive values are not valid for this equation.

Is this a medical measurement of my true max heart rate?

No. Gellish is a population regression from age alone. True individual maximums vary; use clinical or supervised testing when precision matters for health decisions.

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

POSThttps://api.kit.forhosting.com/health/hrmax-gellish

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/hrmax-gellish \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"age":40}'

const res = await fetch("https://api.kit.forhosting.com/health/hrmax-gellish", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "age": 40
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/health/hrmax-gellish",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "age": 40
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/hrmax-gellish", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"age":40}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"age":40}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/hrmax-gellish", 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": 40
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "health.hrmax_gellish",
  "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

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Limits

`max_age`	120
`min_age`	1e-9

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.

Read the full KIT documentation →