{
  "slug": "calories-hiit",
  "title": "Calorie Burn — HIIT & Circuit Training",
  "category": "Energy Expenditure",
  "category_slug": "energy-expenditure",
  "tier": 2,
  "summary": "Estimate calories burned in HIIT and circuit sessions from body weight, duration, and session type.",
  "description": "This calculator estimates the energy cost of interval and circuit sessions using MET values from the Adult Compendium of Physical Activities. It multiplies body weight, session length, and one of four published entries: circuit training at moderate effort, 5.0 METs (code 02035); high-intensity interval exercise at moderate effort, 7.0 METs (code 02210); vigorous circuit training including kettlebells, 7.5 METs (code 02040); and vigorous high-intensity interval exercise with burpees, mountain climbers, and squat jumps, 11.0 METs (code 02214). A single MET flattens the work-rest structure of intervals, a limitation discussed in the notes.",
  "page_url": "https://fitmetriclab.com/en/tools/energy-expenditure/calories-hiit/",
  "api_url": "https://fitmetriclab.com/api/tools/calories-hiit.json",
  "formula": {
    "id": "calories_hiit",
    "expression": "\\text{Calories} = \\text{MET}(\\text{session}) \\times w \\times \\frac{t}{60}",
    "variables": [
      {
        "symbol": "w",
        "description": "Weight in kg"
      },
      {
        "symbol": "t",
        "description": "Duration in minutes"
      },
      {
        "symbol": "\\text{MET}",
        "description": "5.0, 7.0, 7.5, or 11.0 by session type (Compendium codes 02035, 02210, 02040, 02214)"
      }
    ]
  },
  "inputs": [
    {
      "id": "weight_kg",
      "label": "Weight",
      "type": "number",
      "unit": "kg",
      "default": 75,
      "min": 20,
      "max": 300,
      "step": 0.1
    },
    {
      "id": "minutes",
      "label": "Duration",
      "type": "number",
      "unit": "min",
      "default": 30,
      "min": 1,
      "max": 300,
      "step": 1
    },
    {
      "id": "session_type",
      "label": "Session type",
      "type": "select",
      "unit": null,
      "default": 3,
      "options": [
        {
          "label": "Circuit, moderate (5.0 MET)",
          "value": 0
        },
        {
          "label": "HIIT, moderate (7.0 MET)",
          "value": 1
        },
        {
          "label": "Circuit, vigorous — kettlebells, minimal rest (7.5 MET)",
          "value": 2
        },
        {
          "label": "HIIT, vigorous — Tabata, burpees (11.0 MET)",
          "value": 3
        }
      ]
    }
  ],
  "worked_example": {
    "inputs": {
      "weight_kg": 75,
      "minutes": 30,
      "session_type": 3
    },
    "expected_output": "413 kcal"
  },
  "result_summary_template": "A person weighing {weight_kg} kg who trains for {minutes} minutes in the selected session type burns approximately {result}.",
  "methodology": "Calories = MET × body mass (kg) × duration (hours). MET values from the Adult Compendium of Physical Activities (2024): circuit training, moderate effort = 5.0 METs (code 02035); high intensity interval exercise, moderate effort = 7.0 METs (code 02210); circuit training including kettlebells, some aerobic movement with minimal rest, vigorous = 7.5 METs (code 02040); high intensity interval exercise — burpees, mountain climbers, squat jumps, Tabata — vigorous = 11.0 METs (code 02214). Net figure = (MET − 1) × mass × hours.",
  "sources": [
    {
      "label": "Herrmann SD, et al. 2024 Adult Compendium of Physical Activities: a third update of the energy costs of human activities. J Sport Health Sci. 2024;13(1):6–12.",
      "url": "https://pacompendium.com/conditioning-exercise/"
    },
    {
      "label": "Ainsworth BE, et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Med Sci Sports Exerc. 2011;43(8):1575–1581.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/21681120/"
    },
    {
      "label": "Jetté M, Sidney K, Blümchen G. Metabolic equivalents (METS) in exercise testing, exercise prescription, and evaluation of functional capacity. Clin Cardiol. 1990;13(8):555–565.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/2204507/"
    }
  ],
  "faqs": [
    {
      "question": "My intervals feel much harder than 11 METs — is the estimate low?",
      "answer": "The work bursts probably are harder than 11 METs; the rests are far easier. The Compendium value is a whole-session average, so a Tabata block whose 20-second efforts reach 15 METs still averages near 11 once the rest periods are included. Pricing only the work minutes at a burst-level MET double-counts recovery time. For a session logged as work-only minutes, a custom MET entry above 11 can be defensible."
    },
    {
      "question": "Which band fits a typical group fitness HIIT class?",
      "answer": "Most 45-minute classes include warm-up, instruction, transitions, and cool-down around the interval blocks, which dilutes the average intensity. Sessions where genuinely vigorous work fills less than half the clock generally sit nearer the 7.0 MET moderate-interval entry than the 11.0 vigorous one. Classes built on continuous station work with minimal rest match the 7.5 MET vigorous circuit entry reasonably well."
    },
    {
      "question": "Does HIIT keep burning calories after the session ends?",
      "answer": "Post-exercise oxygen consumption is real and is larger after intervals than after steady-state work, but controlled measurements put it around 6–15% of the session's cost — tens of kilocalories for a half-hour workout, not hundreds. This calculator prices the session window only. Counting the result as inclusive of any afterburn keeps daily energy arithmetic on the conservative side."
    },
    {
      "question": "Why does a moderate circuit rate only 5.0 METs when it involves weights?",
      "answer": "Resistance stations tax muscles locally but raise whole-body oxygen uptake modestly, and station transitions, rest between sets, and setup time all count toward the session average. Measured circuit sessions at conversational effort come out near 5.0 METs — similar to brisk walking — even though individual sets feel demanding. Compressing rest and adding ballistic movements is what pushes circuits into the 7.5 MET vigorous entry."
    },
    {
      "question": "How does body weight interact with interval calories?",
      "answer": "Linearly, in this model: a 90 kg athlete is estimated to burn 20% more than a 75 kg athlete in the identical session, because the MET equation scales with mass. For bodyweight-based formats (burpees, squat jumps) that scaling is physically plausible — every rep moves the whole body. For machine-based intervals like bike sprints, real cost tracks external power more than mass, and the linear scaling becomes a rougher approximation."
    }
  ],
  "related_tools": [
    {
      "slug": "calories-jump-rope",
      "title": "Calorie Burn — Jump Rope",
      "api_url": "https://fitmetriclab.com/api/tools/calories-jump-rope.json",
      "page_url": "https://fitmetriclab.com/en/tools/energy-expenditure/calories-jump-rope/"
    },
    {
      "slug": "calories-boxing",
      "title": "Calorie Burn — Boxing",
      "api_url": "https://fitmetriclab.com/api/tools/calories-boxing.json",
      "page_url": "https://fitmetriclab.com/en/tools/energy-expenditure/calories-boxing/"
    },
    {
      "slug": "hiit-ratio",
      "title": "HIIT Work-Rest Ratio Calculator",
      "api_url": "https://fitmetriclab.com/api/tools/hiit-ratio.json",
      "page_url": "https://fitmetriclab.com/en/tools/timing-pacing/hiit-ratio/"
    },
    {
      "slug": "custom-met-calculator",
      "title": "Custom Activity MET Calculator",
      "api_url": "https://fitmetriclab.com/api/tools/custom-met-calculator.json",
      "page_url": "https://fitmetriclab.com/en/tools/energy-expenditure/custom-met-calculator/"
    }
  ],
  "last_updated": "2026-08-08",
  "price": {
    "value": 0,
    "currency": "USD"
  },
  "runs_in_browser": true,
  "disclaimer": "Educational estimate produced from a published formula. Not medical, nutritional, or training advice. Calculations are deterministic — apply the formula to the inputs to reproduce the result."
}