ForHosting KIT · Developer Utilities

BAC calculator

Estimates blood alcohol content (BAC) as a percentage with the Widmark equation from sex, body weight, number of standard drinks and hours elapsed. Educational estimate only, not legal or medical advice.

● 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

Which formula does it use?

The Widmark equation: alcohol_g / (r * weight_kg * 10) minus beta * hours, with r 0.68 for male and 0.55 for female.

What is a standard drink here?

14 grams of alcohol by default (one US standard drink). Change grams_per_drink to model a different definition.

Can I change the elimination rate?

Yes. The beta field defaults to 0.015 BAC percent per hour and can be adjusted; the result is clamped at zero.

Is this legal or medical advice?

No. It is an educational estimate only, not legal or medical advice, and does not authorize driving. Real BAC varies with many factors Widmark ignores.

Why so many decimals?

BAC values are small, so decimals defaults to 4 (range 0 to 4). The API bills only successful calls from $0.002.

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/dev/bac-calculator

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/dev/bac-calculator \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"sex":"male","weight_kg":70,"drinks":2,"hours":2}'

const res = await fetch("https://api.kit.forhosting.com/dev/bac-calculator", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "sex": "male",
    "weight_kg": 70,
    "drinks": 2,
    "hours": 2
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/dev/bac-calculator",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "sex": "male",
    "weight_kg": 70,
    "drinks": 2,
    "hours": 2
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/dev/bac-calculator", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"sex":"male","weight_kg":70,"drinks":2,"hours":2}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"sex":"male","weight_kg":70,"drinks":2,"hours":2}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/dev/bac-calculator", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "sex": "male",
  "weight_kg": 70,
  "drinks": 2,
  "hours": 2
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "dev.bac_calculator",
  "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.

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 →

Run — free