Work out calories and kilojoules burned in a high-intensity interval training session, based on your body weight, total session length, and whether the effort level was moderate or vigorous.
HIIT calorie burn is estimated using a MET (Metabolic Equivalent of Task) value for your effort level, multiplied by your body weight and the total session time — the whole session clock, including the rest periods between work intervals, not just the hard bursts themselves. The formula is calories = MET × body weight in kilograms × time in hours. A 70 kg person doing a 25-minute vigorous HIIT session (MET 11.0 — burpees, mountain climbers, squat jumps, minimal rest) burns approximately 321 kcal, about 1,342 kJ. The same person and duration at a moderate effort (MET 7.0) burns around 204 kcal, about 854 kJ.
| Metric | Value |
|---|
| Intensity | MET | Calories | kJ |
|---|
The calculation uses three inputs: your body weight, the total time your session ran for, and a MET value representing how demanding that intensity level is on average across a full HIIT session. The 2024 Adult Compendium of Physical Activities lists "high-intensity interval exercise, moderate effort" (code 02210, MET 7.0) and "high-intensity interval exercise, vigorous, burpees/mountain climbers/squat jumps" (code 02214, MET 11.0) — both figures are whole-session averages, meaning they were derived by measuring energy expenditure across entire interval sessions that already included their typical rest periods, not just isolated bursts of maximal effort.
It's a common instinct to count only the minutes spent on the hard bursts — the actual burpees, sprints or squat jumps — and leave out the rest in between. Don't: the MET values used here (7.0 for moderate, 11.0 for vigorous) are whole-session averages, meaning researchers tracked energy expenditure across entire HIIT sessions that already contained a realistic mix of work and rest for that intensity tier. Enter the full clock time of your session, from your first work interval to your last, rest periods and all, and the MET value handles the averaging for you. If you instead entered only your active work time, you'd effectively be layering the intensity twice and inflating your result.
The MET value behind this calculator's estimate is a whole-session average, not a measurement of your hardest single moment. A maximal-effort burpee or squat jump partway through a vigorous work interval demands far more from your body than 11 METs — momentary intensity during a work burst sits well above anything a single averaged number can represent. What the MET value actually captures is the net effect across the entire session once every rest period, transition and lighter moment gets blended in with the hard efforts. That's the whole reason the duration field asks for total session time: the averaging already assumes a realistic work-to-rest mix for that intensity tier.
Because HIIT alternates hard efforts with recovery rather than holding one steady pace throughout, its whole-session MET values (7.0 to 11.0) sit well above a comfortable walk or an easy jog, and even above many moderate-paced steady-state cardio sessions. That means a HIIT session can rack up a similar calorie total to a longer steady-state workout in noticeably less overall time — useful when your session length is limited. There's also a small metabolic bonus once the session ends: HIIT tends to produce a somewhat larger EPOC ("afterburn") effect than steady, low-intensity cardio, because the body has more oxygen debt and metabolic byproducts to clear afterward. That effect is real but modest — typically a small percentage on top of the session's calorie burn rather than a separate large workout's worth of extra calories — so it's the time-efficiency of the session itself, not the afterburn, that mainly explains HIIT's high per-minute cost.
The table below holds intensity at vigorous (MET 11.0) and duration at 25 minutes, so you can see how much body weight alone shifts the total.
| Body Weight | MET | Calories (25 min) | Kilojoules |
|---|---|---|---|
| 60 kg | 11.0 | 275 kcal | 1,151 kJ |
| 70 kg | 11.0 | 321 kcal | 1,342 kJ |
| 80 kg | 11.0 | 367 kcal | 1,534 kJ |
| 90 kg | 11.0 | 413 kcal | 1,726 kJ |
| 100 kg | 11.0 | 458 kcal | 1,918 kJ |
Here body weight is fixed at 70 kg and duration at a full hour, so you can compare the two intensity tiers directly.
| Intensity | MET | Calories/hour | Calories/minute |
|---|---|---|---|
| Moderate HIIT | 7.0 | 490 kcal/hr | 8.17 kcal/min |
| Vigorous HIIT | 11.0 | 770 kcal/hr | 12.83 kcal/min |
Australian nutrition panels report energy in kilojoules rather than calories, so it helps to convert your HIIT session into the same unit. Multiply your kcal figure by 4.184 to get kJ. The 70 kg example above, burning 321 kcal in a 25-minute vigorous session, works out to about 1,342 kJ — a handy reference point next to the energy value printed on a post-workout shake, protein bar or recovery snack.
How many calories does a HIIT workout burn?
It depends on your body weight, session length and intensity. Using the MET values in this calculator, a 70 kg person doing a 25-minute session burns around 204 kcal at a moderate effort (MET 7.0) or around 321 kcal at a vigorous effort (MET 11.0, think burpees, mountain climbers and squat jumps). Heavier body weight, longer sessions and a harder effort level all push the total higher — enter your own numbers above for a personalised estimate.
Should I count rest time in the duration I enter?
Yes. Enter the total time the session ran for, including every rest and recovery period between work intervals, not just the minutes spent working hard. The MET values used here (7.0 for moderate, 11.0 for vigorous) are whole-session averages from the Adult Compendium of Physical Activities, and they already factor in a typical work-to-rest ratio for that style of interval training. If you only entered your active work time, the result would overstate your actual calorie burn.
Does the "afterburn effect" (EPOC) add extra calories beyond what's shown?
A small amount, yes. After a hard HIIT session your metabolism stays mildly elevated for a while as your body restores oxygen levels and returns to baseline — this is called excess post-exercise oxygen consumption (EPOC), or "afterburn." Research on HIIT generally puts this extra energy cost at a modest addition on top of the session total, not a dramatic multiplier, so it's worth knowing about but not something to build a large calorie estimate around.
Is HIIT better than steady-state cardio for calorie burn?
HIIT tends to burn calories at a faster rate per minute than gentler steady-state cardio, because the work MET values involved (7.0-11.0 here) are higher than a comfortable jog or cycle. That makes it a time-efficient option when you're short on time. Steady-state cardio, however, can be sustained for much longer and remains a very effective way to burn a large total number of calories in one session — which one produces more total burn often comes down to how long you can keep either one going.
What counts as vigorous vs moderate HIIT?
This calculator uses two Adult Compendium of Physical Activities categories. Moderate HIIT (MET 7.0) describes interval work with more rest between rounds and a more controlled pace throughout. Vigorous HIIT (MET 11.0) describes high-intensity interval exercise built around demanding, explosive movements such as burpees, mountain climbers and squat jumps, with minimal rest between efforts. If your session leans harder and faster with barely any recovery, vigorous is the closer match; if it's a bit more paced with longer breaks, choose moderate.
How long should a HIIT session be?
Most HIIT sessions run somewhere between 10 and 30 minutes, including warm-up, work intervals and rest — genuine high-intensity effort is hard to sustain much longer than that. The right length depends on your fitness level and how the intervals are structured; shorter sessions with harder efforts and longer sessions with more moderate pacing can produce a similar total calorie burn. Enter your own session length above to see how it changes your estimate.
Can beginners do HIIT safely?
Many beginners can, but HIIT is vigorous exercise by design, and it's worth easing in rather than starting at maximum intensity. Choosing the moderate preset, using longer rest periods, and building up session length gradually are sensible ways to start. Anyone new to exercise, returning after a break, or managing an existing health condition should check with a doctor before beginning a HIIT program, since the format's rapid, high-impact movements place more demand on the heart and joints than lower-intensity training.
What are the limitations of MET-based estimates for interval training?
MET values are averages drawn from studies of typical people doing a described activity, so they don't capture your individual fitness level, exact movement selection, or how hard you personally pushed each interval. Two 25-minute vigorous sessions with different exercises, rest lengths or effort levels can burn meaningfully different amounts of energy despite sharing the same MET value. Treat the result as a reasonable planning estimate rather than an exact measurement — for a closer number, a heart-rate-based fitness tracker calibrated to your own data will generally outperform a generic MET calculation.