Mueller equation BMR calculator
Get a composition-aware resting calorie floor from four simple measurements: a 30-year-old man of 80 kg and 180 cm splits into 61.42 kg lean and 18.58 kg fat, and the Mueller equation gives 1784.59 kcal a day. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Weight
- 80
- Height
- 180
- Age
- 30
- Sex
- Male
- Bmr kcal day
- 1,784.59 kcal/day
- Equation
- mueller
- Sex code
- 1
- Weight (kg)
- 80
Basal metabolic rate is the energy your body expends at complete rest to sustain breathing, circulation, cellular repair and core temperature. The Mueller equation estimates that daily calorie floor from lean body mass, fat mass, age and sex, which captures body-composition effects that simple weight-only models miss. This capability derives lean mass with the Boer formula from weight in kilograms, height in centimeters and sex, then applies Mueller with age so you never need a caliper reading or DEXA scan. The result is a transparent kcal-per-day figure for meal planning, clinical notes, wellness products and research pipelines.
What the Mueller equation computes and why it matters
The Mueller equation estimates basal metabolic rate in kilocalories per day from lean body mass, fat mass, chronological age and a binary sex code. The classic form is thirteen point five eight seven times lean mass in kilograms plus nine point six one three times fat mass plus one hundred ninety-eight times sex code minus three point three five one times age plus six hundred seventy-four, where sex code is one for male and zero for female.
Lean mass carries a higher coefficient than fat mass because metabolically active tissue drives most of resting expenditure; age reduces the estimate to reflect typical declines in resting energy; and the sex term captures average differences observed in validation cohorts. Unlike Mifflin-St Jeor or revised Harris-Benedict, which fold composition into weight, height and sex coefficients alone, Mueller makes the lean-versus-fat split explicit. That is valuable when you care about how two people of the same scale can rest at different calorie floors.
This capability still accepts only weight, height, age and sex at the public surface: lean mass is estimated with the Boer equations from weight and height, and fat mass is total weight minus lean mass. The output remains a resting energy floor, not total daily energy expenditure—it does not add exercise, NEAT, thermic effect of food or illness-related demand. Use it as a composition-aware baseline, then layer activity factors or measured intake when you need a full budget.
Where it fits in real health and product workflows
Nutrition coaching apps that already collect height and weight at onboarding can show a Mueller baseline next to Mifflin or Harris-Benedict so clients see how composition-aware models differ without asking for body-fat percentage. Clinical research coordinators batch-convert study-subject measurements into BMR for secondary analysis without spreading spreadsheet formulas that diverge by cell or rounding mode. Fitness platforms display a transparent resting figure beside wearable burn estimates so members understand the floor versus the daily total.
Employer wellness portals and insurance education tools pre-fill calculators without shipping proprietary engines or third-party nutrition APIs.
What you can do with it
Composition-aware onboarding baselines
Convert weight, height, age and sex collected at signup into a Mueller BMR without requiring a body-fat measurement.
Side-by-side model transparency
Show users Mueller kcal/day next to Mifflin or Harris-Benedict so product dashboards explain model choice clearly.
FAQ
What does it cost?
The same calculation runs free in your browser on this page.
Which units does the formula expect?
Weight in kilograms, height in centimeters, age in years. Convert from pounds or inches before calling.
Is this total daily energy expenditure (TDEE)?
No. This returns basal metabolic rate only. Multiply by an activity factor yourself if you need estimated TDEE.
Why was my request rejected?
Weight and height must be positive numbers. Age must be non-negative and at most 130. Sex must be male or female (or m/f/man/woman). Anthropometrics that produce non-positive Boer lean mass or lean mass at or above total weight are also rejected.
How does Mueller differ from Mifflin-St Jeor?
Mueller uses separate coefficients for lean and fat mass plus an explicit sex code and age term. This capability estimates lean mass with Boer from weight and height so you still only supply four anthropometric fields. Mifflin-St Jeor applies fixed weight, height, age and sex constants without an intermediate composition step.
Related tools
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/bmr-mueller \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"weight":80,"height":180,"age":30,"sex":"male"}'const res = await fetch("https://api.kit.forhosting.com/health/bmr-mueller", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"weight": 80,
"height": 180,
"age": 30,
"sex": "male"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/health/bmr-mueller",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"weight": 80,
"height": 180,
"age": 30,
"sex": "male"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/bmr-mueller", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"weight":80,"height":180,"age":30,"sex":"male"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"weight":80,"height":180,"age":30,"sex":"male"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/bmr-mueller", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"weight": 80,
"height": 180,
"age": 30,
"sex": "male"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "health.bmr_mueller",
"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. |
Technical notes
How to call the API and interpret the fields
Send four required fields: weight as a positive number in kilograms, height as a positive number in centimeters, age as a non-negative number of years at most one hundred thirty, and sex as male or female (short forms m, f, man and woman are accepted). There is no network hop, model call or randomness, so latency stays in the pure edge-parse band. Pair this result with your own activity multiplier (for example one point two sedentary through one point nine very active) if you need estimated TDEE; this capability deliberately stops at BMR so product copy and clinical tools stay honest about what was measured. Aliases such as weight_kg, height_cm, kg, cm, years, age_years and gender map to the same parameters so existing forms wire in without renaming. Non-positive weight or height fail immediately with invalid_input and are not charged; missing or unparseable sex or age also raise invalid_input with a clear field name. If Boer lean mass is not positive or meets or exceeds total weight for the given anthropometrics, the request is rejected rather than returning a nonsensical composition split. A successful response returns bmr_kcal_day rounded to two decimal places, the normalized sex and sex_code, the numeric inputs used, lean_mass_kg and fat_mass_kg from Boer, equation set to mueller, lbm_method set to boer, a human-readable formula string and the unit label kcal/day.
Where it fits in real health and product workflows
Developers embed the call in CRON jobs and webhooks so every service shares one definition of Mueller-plus-Boer instead of reimplementing float-sensitive multiplies that disagree on the second decimal. The API path costs $0.002 per successful request and is billed per item, which keeps bulk onboarding scripts cheap while still covering edge execution.
Integration use cases
Clinical and research pipelines
Batch-compute resting energy estimates for study subjects with one audited formula and stable JSON output.