Body composition check

Skinfold calipers

An estimate of your body fat from skinfold thickness, measured with calipers. It is the only check here that estimates body fat.

Start the check
  • About 8 minutes
  • Free, and no account needed
  • Not a diagnosis

01Understand the check

What skinfold calipers can tell you

An estimate of your body fat, from skinfolds.

  • What it measures

    The thickness of skinfolds at 3 or 7 sites, in millimetres, turned into an estimate of your body fat. It is the only check here that estimates body fat.

  • What it can't tell you

    Your exact body fat. Measured by trained testers, these formulas were usually within about 3.5 to 4 percentage points of laboratory methods; measuring yourself is usually less accurate.

  • What you need

    Skinfold calipers, about 8 minutes and, ideally, someone to help. Your age and sex too: the sites and the ratings depend on them.

02Take the check

Choose a method and measure each site

In millimetres, on the right side of your body.

Body Fat Caliper Assessment

Select Test Method:

Diagonal fold between nipple and armpit
Vertical fold 2cm beside belly button
Front of thigh, midway between knee and hip
Vertical fold on back of arm, midway between shoulder and elbow
Diagonal fold below shoulder blade
Diagonal fold above hip bone
Horizontal fold at armpit level on side

Add your age and sex Needed for a rating

Some assessments compare your result with people of the same age and sex, so they can only give a rating once they know both. Sneaky will not guess. What you enter here stays on this device.

Move the slider towards the end that applies to you. The middle means “not stated”, and an assessment that compares by sex will then not give a rating.

Login Register

Sneaky works your result out on its own servers the moment you press this, not with AI.

03Your result

Your result appears here

As soon as you calculate.

Your body-fat estimateits rating

You'll see your estimated body fat as a percentage, its rating for your age and sex, and the sites you measured.

Worked out by Sneaky's own health maths, not by AI.

Body-fat ratings for your age and sex, from High to Excellent
  1. High
  2. Average
  3. Good
  4. Excellent

04Next steps

Where to go from here

One result is one clue. Add to the picture.

Complete the picture

Or do all 3 body composition checks together, about 18 minutes plus rests, with one report: Body composition assessment.

Full Analysis

All 13 checks, one report

Every check one at a time, in seven chapters, ending with one report: your stronger results, the areas to work on and how your left and right sides compare. Pause any time.

Take the Full Analysis

Beyond this check

See all 13 checks

05Good to know

Good to know

Quick answers about skinfold calipers.

Three sites or seven?

Three sites is quicker; seven gives the formula more to work with. The sites you see depend on the method and on the sex in your profile. Use the same method each time so your report can compare your results directly.

How should I read my result?

As an estimate of your body fat, rated with the bands for your age and sex. "Very Low" is shown as a flag rather than a rating: it is worth talking to a doctor about.

How accurate is it?

It is an estimate. Measured by trained testers, these formulas were usually within about 3.5 to 4 percentage points of laboratory methods. Measuring yourself is usually less accurate, and the estimate is least reliable at very low or very high skinfold totals.

Can I measure myself?

You can, but some sites are hard to reach. A helper who measures the same way each time gives steadier results. Measure on the right side of your body, two or three times per site, and use a reading you get consistently.

How often should I re-measure?

Every four to eight weeks. Body fat changes slowly, so more frequent readings mostly show measuring differences.

When should I stop or get help?

Pinch gently, don't measure over broken or sore skin, and stop if it hurts. If your result shows "Very Low", or your body fat has changed a lot without a clear reason, talk to a doctor.

If a result worries you, or you have symptoms, an injury or a health condition, talk to a doctor or another qualified professional. This check gives general information, not a diagnosis or medical advice.

More answers in the FAQ

Learn more about skinfold calipers5 short sections: what it measures, how it works, how to read it and how to use it

What the Calipers Test Measures and Why It Matters

The calipers (skinfold) test estimates your body fat percentage by measuring the thickness of fat just beneath your skin.

Unlike weight or BMI, this test gives you a much clearer picture of your body composition — how much of your body is fat vs lean mass.

This matters because body fat percentage is closely linked to:

  • Metabolic health
  • Hormonal balance
  • Physical performance
  • Long-term disease risk

Two people can weigh the same but have completely different body fat levels — and very different health profiles.

This test helps you move beyond the scale and understand what’s really happening in your body.

How the Test Works and Its Accuracy

The calipers test uses simple measurements taken at specific points on your body.

Depending on the method you choose:

3-Site Test (Faster)

  • Chest
  • Abdomen
  • Thigh

7-Site Test (More Detailed)

  • Chest
  • Abdomen
  • Thigh
  • Triceps
  • Subscapular (upper back)
  • Suprailiac (above hip)
  • Midaxillary (side of torso)

You measure each site using calipers, then input the values to estimate your body fat percentage.

Accuracy

  • 7-site test → higher accuracy
  • 3-site test → faster, still reliable

Results depend heavily on measurement consistency, not just the formula.

Even if your numbers aren’t perfect, this test is extremely valuable for tracking changes over time, which is what really matters.

How to Interpret Your Results

Your result shows your estimated body fat percentage, along with a category.

General Ranges

Men:

  • Essential: 2–5%
  • Athletic: 6–13%
  • Fit: 14–17%
  • Average: 18–24%
  • High: 25%+

Women:

  • Essential: 10–13%
  • Athletic: 14–20%
  • Fit: 21–24%
  • Average: 25–31%
  • High: 32%+

What matters most

  • Lower isn’t always better — extremely low body fat can affect hormones and energy
  • Your trend over time is more important than a single reading
  • Your category + how you feel gives better insight than the number alone

Practical Guidance for Best Results

To get the most accurate and useful results:

  • Use consistent technique — same locations, same side of the body
  • Measure 2–3 times per site and average the values
  • Test under similar conditions (time of day, hydration, etc.)
  • Don’t rush — precision matters more than speed

Important

You don’t need perfect measurements to get value from this test.

Consistency beats perfection.

If you measure the same way each time, you’ll clearly see whether your body fat is going up or down — and that’s what drives real progress.

Final Note

The calipers test is one of the most practical ways to track real body composition changes at home.

It’s not about chasing a perfect number — it’s about understanding your body and improving over time.

Small changes in body fat percentage can reflect meaningful improvements in your health, performance, and overall fitness.