Metabolism calculator (BMR / RMR / TDEE profile) API

Full metabolic profile in one call: BMR via Mifflin-St Jeor (primary), Harris-Benedict (revised 1984), and Katch-McArdle (when bodyFatPct is given), RMR, TDEE across all five activity levels, goal calorie targets (cut/maintain/bulk), and a rough metabolic-age estimate. Estimate, not medical advice. Answers 'what is my BMR and TDEE', 'how many calories to lose or gain weight', 'metabolism calculator', 'what is my metabolic age'.

Price$0.01per request

MethodPOST

Route/v1/health/metabolism

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

healthmetabolismbmrrmrtdeecaloriesfitnessmetabolic-age

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

Integration docs

Example request

{
  "weightKg": 75,
  "heightCm": 180,
  "ageYears": 30,
  "sex": "male",
  "activity": "moderate"
}

Example response

{
  "sex": "male",
  "bmrKcalPerDay": 1730,
  "bmrFormulas": {
    "mifflinStJeor": 1730,
    "harrisBenedict": 1769,
    "katchMcArdle": null
  },
  "rmrKcalPerDay": 1730,
  "tdeeKcalPerDay": 2682,
  "tdeeByActivity": {
    "sedentary": 2076,
    "light": 2379,
    "moderate": 2682,
    "active": 2984,
    "veryActive": 3287
  },
  "calorieTargets": {
    "cut": 2182,
    "maintain": 2682,
    "bulk": 3182
  },
  "metabolicAgeEstimateYears": 28
}

Input schema

{
  "type": "object",
  "required": [
    "weightKg",
    "heightCm",
    "ageYears",
    "sex"
  ],
  "properties": {
    "weightKg": {
      "type": "number",
      "examples": [
        75
      ]
    },
    "heightCm": {
      "type": "number",
      "examples": [
        180
      ]
    },
    "ageYears": {
      "type": "number",
      "examples": [
        30
      ]
    },
    "sex": {
      "type": "string",
      "enum": [
        "male",
        "female"
      ],
      "examples": [
        "male"
      ]
    },
    "bodyFatPct": {
      "type": "number",
      "examples": [
        18
      ]
    },
    "activity": {
      "type": "string",
      "enum": [
        "sedentary",
        "light",
        "moderate",
        "active",
        "veryActive"
      ],
      "examples": [
        "moderate"
      ]
    }
  }
}

Output schema

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