MET Values Explained: The Number Behind Every Estimate

Every number Cal Core shows you traces back to a single value attached to each activity: its MET. If you understand what a MET is, you understand the whole calculator — and you can read any fitness estimate with a much more critical eye. It's a genuinely useful concept, and it takes about five minutes to get.

What a MET actually measures

MET stands for Metabolic Equivalent of Task. It's a ratio: how much energy an activity costs compared to sitting quietly. Sitting still is defined as 1 MET. An activity rated at 4 MET burns four times as much energy per minute as sitting. An activity at 10 MET burns ten times as much.

That's the whole idea. It's a way of putting wildly different activities — swimming, gardening, boxing — on a single comparable scale of intensity. One MET corresponds to consuming about 3.5 millilitres of oxygen per kilogram of body weight per minute, which is the average person's resting metabolic rate.

Where the numbers come from

MET values aren't invented per app. They come from the Compendium of Physical Activities, a reference dataset first published in the 1990s and updated since, which assigns a measured energy cost to hundreds of activities based on laboratory research. When Cal Core says running is 9.8 MET or yoga is 2.5 MET, those figures come from this shared scientific source — the same one used by researchers and public-health guidelines.

We document the exact citation and how we apply these values on our methodology page.

How a MET becomes a calorie count

On its own, a MET value doesn't give you calories — you need to fold in your body weight and how long you move. The standard equation is:

Take a 70 kg person cycling at a moderate 8 MET. That's 8 × 3.5 × 70 ÷ 200 ≈ 9.8 calories per minute, or about 294 calories in half an hour. Swap in a 90 kg rider and the same ride burns closer to 378 calories — the weight term does real work in the formula.

Reading MET values sensibly

Once you know the scale, a few rules of thumb make it easy to interpret any activity:

• Below 3 MET is light activity — gentle walking, most household chores, restorative yoga.
• 3 to 6 MET is moderate — brisk walking, easy cycling, recreational doubles tennis.
• Above 6 MET is vigorous — running, competitive sport, hard interval work.

Public-health guidance is often written in these terms, which is why the scale is worth knowing beyond this calculator: "150 minutes of moderate activity a week" roughly means 150 minutes in that 3–6 MET band.

What MET values quietly leave out

A MET is an average, and averages hide things. Being honest about the gaps is part of using the number well:

• You aren't average. Your resting metabolism can differ from the assumed baseline by 10–15%, which shifts every estimate built on it.
• Effort within an activity varies."Cycling" spans a gentle flat spin and a brutal climb; a single MET value can only represent one point on that range.
• Afterburn isn't counted. Intense sessions elevate your metabolism for hours afterward — real energy the per-minute formula ignores.
• Fitness changes the cost. A trained athlete often moves more efficiently, burning slightly less for the same output. Cal Core approximates this with an optional fitness-level multiplier.

The takeaway

Treat MET-based numbers as a well-calibrated estimate, not a measurement. They're excellent for comparing activities and building intuition about effort, and they're within about 10–20% of reality for most people. That's more than good enough to answer the question Cal Core exists for: roughly how long would it take me to burn this off?

Want to see it in action? Browse the full activity list — each one shows its MET value and the burn time that follows from it.