How many calories does water aerobics burn?

At 5.3 METs, a 70 kg person uses about 186 kcal in thirty minutes. Energy use scales with body weight, so a 90 kg person uses roughly a third more for the same session.

What is the MET value for water aerobics?

5.3 METs, listed under Compendium code 02120. A MET is a multiple of resting metabolic rate.

Should I subtract my resting metabolism?

If you are adding this to a maintenance figure that already includes rest, yes. The net figure removes the roughly one MET-hour per hour your body would have spent anyway, which for water aerobics leaves about 81 per cent of the gross total.

Why does body weight change the answer?

A MET value is energy per kilogram of body mass, so the same activity costs more for a heavier body. That is why weight is an input rather than an assumption, and why generic calories-burned figures without a weight are close to meaningless.

How accurate is this figure?

It is an estimate from a population average. Published comparisons against indirect calorimetry find individual discrepancies of twenty to thirty per cent, so use it to compare activities rather than as a ledger to eat back.

Calories burned water aerobics

Water aerobics is rated at 5.3 METs, meaning it costs about 5.3 times as much energy per minute as sitting still. Enter your weight and duration to turn that into kilocalories.

Result

These are estimates from population-level equations, not a measurement of you and not medical advice. Individual results vary widely. Talk to a doctor or a registered dietitian before making significant changes to how you eat or train.

The MET value and where it comes from

MET value: 5.3
Compendium code: 02120
Listed as: Water aerobics, water calisthenics, water exercise
Category: Water

The Compendium assigns water aerobics a value of 5.3 METs. One MET is what sitting quietly costs, so this activity is about 5.3 times that per minute of doing it.

kcal = MET × kg × h
     = 5.3 × weight × hours

net of resting:
kcal = (5.3 − 1) × weight × hours

Source: Herrmann SD, Willis EA, Ainsworth BE, et al. "2024 Adult Compendium of Physical Activities." Journal of Sport and Health Science 13(1), 2024, pp. 6–12. MET values are population averages; roughly 18% of Compendium entries are estimated rather than measured.

The figure above is gross energy — everything spent during the session, including the resting metabolism you would have used anyway. Subtracting one MET-hour per hour gives what water aerobics actually added.

The 5.3 MET figure for water aerobics is a population average. The Compendium itself notes that individual energy cost varies with fitness, technique, terrain and body composition, so treat it as an order of magnitude rather than a measurement.

Calories burned by body weight and duration

Gross energy in kilocalories. Read across from your weight and down from your duration. A 70 kg person uses about 371 kcal an hour, of which roughly 301 is above what resting would have cost.

Calories burned by body weight and duration
Body weight	15 min	20 min	30 min	45 min	60 min	90 min
55 kg	73	97	146	219	292	437
65 kg	86	115	172	258	345	517
75 kg	99	133	199	298	398	596
85 kg	113	150	225	338	451	676
95 kg	126	168	252	378	504	755
110 kg	146	194	292	437	583	875

Compared with related activities

Energy used per thirty minutes at 70 kg, so the activities are directly comparable.

Comparison with related activities
Activity	METs	kcal / 30 min
Water aerobics	5.3	186
Swimming, slow freestyle	5.8	203
Low-impact aerobics	4.8	168
Pilates	2.8	98
Power yoga	4	140
Swimming, fast freestyle	9.8	343

Questions

How many calories does water aerobics burn?: At 5.3 METs, a 70 kg person uses about 186 kcal in thirty minutes. Energy use scales with body weight, so a 90 kg person uses roughly a third more for the same session.
What is the MET value for water aerobics?: 5.3 METs, listed under Compendium code 02120. A MET is a multiple of resting metabolic rate.
Should I subtract my resting metabolism?: If you are adding this to a maintenance figure that already includes rest, yes. The net figure removes the roughly one MET-hour per hour your body would have spent anyway, which for water aerobics leaves about 81 per cent of the gross total.
Why does body weight change the answer?: A MET value is energy per kilogram of body mass, so the same activity costs more for a heavier body. That is why weight is an input rather than an assumption, and why generic calories-burned figures without a weight are close to meaningless.
How accurate is this figure?: It is an estimate from a population average. Published comparisons against indirect calorimetry find individual discrepancies of twenty to thirty per cent, so use it to compare activities rather than as a ledger to eat back.