How to Measure Skinfolds Properly (4 Sites)

Skinfolds have been around forever. People love to call them outdated. But when you do them properly, they’re still one of the best ways to track fat loss without getting obsessed with the scale.

Not because they give you a “perfect” body fat percentage, but because they show what’s happening under the skin over time.

That’s what you actually need if you’re training, dieting, and trying to change your body in a way that lasts.

Skinfolds work when you do them right

A scale can jump up and down from water, stress, travel, bad sleep, and one high salt meal. That’s normal. Skinfolds are different.

They measure the thickness of the fat layer under your skin at the same spots each time. When your measurements go down over weeks, you’re leaning out. When they go up, something is drifting.

It’s simple.The only problem is that skinfolds are only as good as your technique.

General rules before you start

Pick one method and stick to it.
Measure the same day each time.
Measure at the same time of day.
Use the same caliper.
Use the same person measuring if possible.

If you keep changing the process, the data becomes noise.

What you need

• A skinfold caliper

• A mirror or a partner

• A notes app to log the numbers
  

• Two minutes of patience

The 4 sites we use

Biceps - Front of the upper arm, halfway between shoulder and elbow. Vertical fold.

Triceps - Back of the upper arm, halfway between shoulder and elbow. Vertical fold.

Subscapular - Just below the bottom tip of the shoulder blade. Diagonal fold.

Suprailiac - Just above the hip bone on the side of the body. Diagonal fold.

Pick one side and stay consistent. The right side is standard, but the real rule is - same side, same place svery time.

The pinch

Do not grab the muscle. Lift the skin and the fat layer underneath it, away from the muscle.

Use your thumb and index finger. Pinch firmly and hold the pinch the whole time.

Caliper placement

The jaws should sit perpendicular to the fold. Don’t angle it. Don’t twist it.

Place the caliper about one centimeter below your fingers, while you keep holding the pinch.

Then let the caliper do its job.

Don’t squeeze harder to “get a better reading”. That makes it worse.

Timing the reading

Once the caliper is placed, wait one to two seconds.

Reading too fast gives a higher number. Waiting too long compresses the tissue and gives a lower number.

This is why skinfolds are all about repeatability.

How many readings per site

Never take one reading, do 2 to 3 readings per site. If the numbers are close, average them.
If one reading is clearly off, ignore it and re-measure.

Small errors add up fast once you start summing skinfolds.

What matters the most

The sum of your skinfolds matters more than the body fat percentage. The percentage is an estimate based on population equations. It’s useful, but it’s not the main point. The sum is your real data.

If the sum goes down over weeks, you’re losing fat.
If it goes up, something is going the wrong way.
If it stays flat while strength goes up, you might be recomposing.

This is how you track progress without losing your mind.

Common mistakes

- Measuring at random times and random days
- Changing the site slightly every time
- Pinching too shallow or too deep
- Letting go of the pinch too early
- Using cheap calipers with inconsistent pressure
- Switching between different people measuring

If you want skinfolds to work, treat them like a process. Not a guess.

How often should you measure

Every 2 to 4 weeks is enough for most people.

Weekly can work if you’re in a fat loss phase and you’re consistent with technique. But don’t overreact to small changes.The trend is what matters.

What to do with the results

If your sum is trending down and your strength is holding, you’re doing it right.

If your sum is flat for 4 weeks, adjust one thing.
Increase daily steps.
Tighten one meal.
Reduce snacking.

If your sum drops fast but training performance crashes, you’re pushing too hard. Protect strength. That’s the base.

Use the Skinfold Body Fat Calculator here.

If you want me to help you measure correctly, interpret your numbers, and build a plan to improve results, book a free assesment call here.