Basal Metabolic Rate (Mifflin-St Jeor) API

Estimate resting daily calorie burn via the Mifflin-St Jeor equation (10·kg + 6.25·cm − 5·age, +5 male / −161 female), returning the value, sex constant, and per-term breakdown for auditability. Answers 'what's my BMR', 'how many calories do I burn at rest', 'basal metabolic rate for 80kg male age 30'.

Price$0.01per request

MethodPOST

Route/v1/health/bmr

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

healthbmrmetabolismmifflin-st-jeorcaloriestdeefitnesscalculator

API URLhttps://x402.hexl.dev/v1/health/bmr

Integration docs

Example request

{
  "weightKg": 80,
  "heightCm": 180,
  "ageYears": 30,
  "sex": "male"
}

Example response

{
  "bmrKcalPerDay": 1780,
  "formula": "Mifflin-St Jeor: 10*kg + 6.25*cm - 5*age + (male:+5 / female:-161)",
  "sex": "male",
  "inputs": {
    "weightKg": 80,
    "heightCm": 180,
    "ageYears": 30
  },
  "breakdown": {
    "fromWeight": 800,
    "fromHeight": 1125,
    "fromAge": -150,
    "sexConstant": 5
  }
}

Input schema

{
  "type": "object",
  "required": [
    "weightKg",
    "heightCm",
    "ageYears",
    "sex"
  ],
  "properties": {
    "weightKg": {
      "type": "number",
      "examples": [
        80
      ]
    },
    "heightCm": {
      "type": "number",
      "examples": [
        180
      ]
    },
    "ageYears": {
      "type": "number",
      "examples": [
        30
      ]
    },
    "sex": {
      "type": "string",
      "enum": [
        "male",
        "female"
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}