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HIIT calorie calculator

Estimate calories burned during HIIT from your weight, session length, and interval intensity using Compendium METs.

Units
Intensity

Session calorie estimates are not a medical exercise prescription. Do not eat a workout twice if it is already inside TDEE.

What this tool does

Enter how many minutes your HIIT session ran and how hard the work intervals felt. The MET applies to total clock time — work plus built-in rest — so type the minutes you were exercising, not the hour you were in the building.

How it works

Vigorous circuit and interval training in the 2011 Compendium sits near 8 MET (moderate), 10 MET (hard), and 12 MET (very hard). Output is gross burn: MET × kg × hours. EPOC (afterburn) is real but usually adds only tens of kilocalories — we do not stack a fantasy bonus.

Formula and methodology

kcal ≈ MET × weight (kg) × time (hours). Session MET is an average across work and rest, not work-interval peak only.

How to interpret the result

A 70 kg adult at hard (10 MET) for 25 minutes: 10 × 70 × 25/60 ≈ 292 kcal gross. Most 20–30 minute classes land near 200–400 kcal — not 1,000. Compare the number to your daily target from the TDEE calculator, not a branded poster.

Example

80 kg, 20 minutes, moderate (8 MET): 8 × 80 × 1/3 ≈ 213 kcal. Same clock at very hard (12 MET): 320 kcal. A 30-minute hard block at 10 MET is about 400 kcal.

Common mistakes

  • Logging the full hour for a 25-minute class plus stretching and selfies.
  • Eating back afterburn or watch calories already counted in TDEE.
  • Doing HIIT daily on a large deficit and wondering why sleep and lifts died.

When this estimate may be off

  • The class was mostly coaching, setup, and foam rolling.
  • You have a clinical condition that makes high-intensity work inappropriate — ask a clinician.

Frequently asked questions

How many calories does a 20-minute HIIT workout burn?

For many adults, 200–350 kcal gross is typical at 8–12 MET. A 70 kg person at hard (10 MET) for 20 minutes is about 233 kcal. Heavier bodies and harder intervals sit higher.

How many calories does HIIT burn per minute?

Roughly MET × kg ÷ 60. At 10 MET and 70 kg that is about 11–12 kcal/min gross. Rest intervals inside the session lower the session average — type total clock time.

Does HIIT burn more than steady cardio?

Per minute, often yes. Per week, the session you will actually repeat wins. Many people last longer on a brisk walk than seven heroic classes.

What about afterburn (EPOC)?

EPOC exists and research often puts it near 6–15% of session burn — tens of kilocalories, not hundreds. We show session calories only; no inflated tail.

Should I eat back HIIT calories?

Only if your TDEE line did not already assume an active day. Garmin and Apple Watch often overstate sweaty classes — do not stack that on top of a very active multiplier.

Is a 1,000-calorie HIIT class realistic?

Not for a typical 20–30 minute class on a typical adult at 8–12 MET. That poster assumes a huge body, a long clock, and invented afterburn.

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