Docs/APIs/BMI Calculator

BMI Calculator

Calculate BMI, BMR, TDEE and nutrition targets

OperationalCredits 2 per callp50 467msHealth/WellnessStar

Overview

BMI Calculator uses the Mifflin-St Jeor equation for accurate BMR calculations and evidence-based activity multipliers for TDEE. It provides actionable data for fitness apps, health trackers, and nutrition planning tools.

Live Test BMI Calculator API →

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

GEThttps://api.apiverve.com/v1/bmicalculator
curl "https://api.apiverve.com/v1/bmicalculator?weight=180&height=70&unit=imperial&age=30&gender=male&activityLevel=moderate" \
  -H "x-api-key: your_api_key_here"

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Parameters

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them.

ParameterTypeDescription
weightRequirednumberWeight in kg (metric) or lbs (imperial)
range 1–∞
heightRequirednumberHeight in cm (metric) or inches (imperial)
range 1–∞
unitRequiredstringUnit system for weight and height
metricimperial
ageOptionalnumberAge in years (required for BMR/TDEE calculations)
range 1–120
genderOptionalstringGender (required for BMR/TDEE calculations)
malefemale
activityLevelOptionalstringActivity level (required for TDEE/calorie calculations)
sedentarylightmoderateactiveveryactive

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

Sample response
{
  "status": "ok",
  "error": null,
  "data": {
    "height": "70 inches",
    "weight": "180 lbs",
    "bmi": 25.83,
    "bmiPrime": 1.033,
    "category": "Overweight",
    "risk": "Increased risk",
    "summary": "BMI is above the healthy range. Lifestyle changes may be beneficial.",
    "idealWeightRange": {
      "min": 129,
      "max": 173.5,
      "unit": "lbs"
    },
    "weightToChange": {
      "direction": "lose",
      "amount": 6.5,
      "unit": "lbs"
    },
    "bmr": 1783,
    "tdee": 2763,
    "calorieTargets": {
      "extremeDeficit": 1763,
      "moderateDeficit": 2263,
      "maintain": 2763,
      "moderateSurplus": 3063,
      "bulkSurplus": 3263
    },
    "macros": {
      "lose": {
        "protein": 198,
        "carbs": 198,
        "fat": 75
      },
      "maintain": {
        "protein": 207,
        "carbs": 276,
        "fat": 92
      },
      "gain": {
        "protein": 230,
        "carbs": 345,
        "fat": 85
      }
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

FieldTypeExampleDescription
heightstring"70 inches"Formatted height with unit
weightstring"180 lbs"Formatted weight with unit
bminumber25.83Calculated Body Mass Index
bmiPrimePremiumnumber1.033Ratio of BMI to upper normal limit (25). Values <1 are normal weight.
categorystring"Overweight"BMI category (Underweight, Normal, Overweight, Obese Class I/II/III)
riskPremiumstring"Increased risk"Health risk level based on BMI category
summaryPremiumstring"BMI is above the healthy range. Lifestyle changes may be beneficial."Brief interpretation of BMI results
idealWeightRangeobject{...}Healthy weight range for this height (min, max, unit)
minnumber129Lowest weight in the healthy BMI range
maxnumber173.5Highest weight in the healthy BMI range
unitstring"lbs"Unit the ideal weight range is expressed in (lbs or kg)
weightToChangePremiumobject{...}Weight to lose or gain to reach normal BMI (direction, amount, unit)
directionPremiumstring"lose"Whether weight needs to be lost, gained, or maintained
amountPremiumnumber6.5How much weight to lose or gain to reach the healthy range
unitPremiumstring"lbs"Unit the weight change is expressed in (lbs or kg)
bmrPremiumnumber1783Basal Metabolic Rate - calories burned at rest (requires age, gender)
tdeePremiumnumber2763Total Daily Energy Expenditure - calories burned per day (requires age, gender, activityLevel)
calorieTargetsPremiumobject{...}Daily calorie targets for different goals (extremeDeficit, moderateDeficit, maintain, moderateSurplus, bulkSurplus)
extremeDeficitPremiumnumber1763Daily calories for aggressive weight loss, roughly 1000 below maintenance
moderateDeficitPremiumnumber2263Daily calories for steady weight loss, roughly 500 below maintenance
maintainPremiumnumber2763Daily calories to hold current weight, equal to total daily energy expenditure
moderateSurplusPremiumnumber3063Daily calories for lean weight gain, roughly 300 above maintenance
bulkSurplusPremiumnumber3263Daily calories for faster weight gain, roughly 500 above maintenance
macrosPremiumobject{...}Macronutrient targets in grams (protein, carbs, fat) for lose/maintain/gain goals
losePremiumobject{...}Daily macronutrient grams for the weight loss calorie target
proteinPremiumnumber198Grams of protein per day while losing weight
carbsPremiumnumber198Grams of carbohydrate per day while losing weight
fatPremiumnumber75Grams of fat per day while losing weight
maintainPremiumobject{...}Daily macronutrient grams for the maintenance calorie target
proteinPremiumnumber207Grams of protein per day at maintenance
carbsPremiumnumber276Grams of carbohydrate per day at maintenance
fatPremiumnumber92Grams of fat per day at maintenance
gainPremiumobject{...}Daily macronutrient grams for the weight gain calorie target
proteinPremiumnumber230Grams of protein per day while gaining weight
carbsPremiumnumber345Grams of carbohydrate per day while gaining weight
fatPremiumnumber85Grams of fat per day while gaining weight

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

StatusMeaningWhat to do
400Input was rejectedRead error; it names the parameter.
401Key missing or invalidCheck the header name and the key value.
403Key valid, but not permittedA key restriction or IP allow-list; see key scoping.
429Rate limited, or out of creditsRead error to tell them apart; see rate limits.

Use cases

Fitness Apps
Calculate BMI, BMR, TDEE and macro targets for users tracking their fitness journey.
Health Tracking
Provide users with their ideal weight range and how much to gain or lose to reach a healthy BMI.
Nutrition Planning
Generate personalized calorie and macronutrient targets for meal planning applications.
Weight Loss Programs
Calculate calorie deficits and protein targets for weight loss applications.

Other ways to use BMI Calculator

Set up BMI Calculator on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKit →Reference →
Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →
Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContext →Reference →

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