When one considers the emphasis many place on achieving their best possible shape physically, it is no surprise the supplement and training industries are booming. There are many approaches to getting, and staying, in shape, with the majority of these revolving around diets and training plans.

However, to achieve superior conditioning, many turn to new and innovative ways to measure their progress. Body-fat measurement has for some time been considered an ideal way to chart physical improvement, with various skin-fold techniques generally considered the most convenient, accessible and cost-effective way.

Indeed, the measurements taken from a skin-fold body-fat test, provide a very good indication of ones body-fat levels. Skin-fold measurements can be converted into a percentage, which can be compared to various norms, and improvements in diet and/or training intensity can subsequently be made to further strip body-fat, to meet physical objectives.

Although a good way in which to chart progress, it should be said that calipers cannot be totally accurate. In fact, in some circles it is thought that skin-fold measurements, not body-fat percentage, will provide greater accuracy when monitoring changes. Rob Thoburn, scientific advisor for BSN nutrition, remembers using calipers in exactly this way.

"I was working for a supplement company several years ago and a group of us guys in R&D would have these in-house body fat competitions.

"We would measure ourselves with calipers. We wouldn't use any complicated formula to figure out our body fat percentage. We simply added up the measurements we got with the calipers on different locations in the body.

"And it worked fine. As long as you have the same person (maybe yourself) take measurements in the same way each time, then you will get relatively useful data."

In today's world, many either want to rid themselves of excess body-fat to improve their health, enhance their physical presence, or both. As bodybuilders, we generally want to shed any visible body-fat to accentuate underlying muscles, and highlight hard-fought definition.

To plan for this fat-loss, it is important to know exactly where one is at and to regularly chart progress for ongoing results. Body-fat percentage can be ascertained and monitored with caliper testing. Calipers are the apparatus used to measure various skin-fold thicknesses, at specific sites, to acquire a percentage value. Generally speaking, a successful result is one which places an individual within a desirable range for their gender and age.

Bodybuilders and other fitness enthusiasts, on the other hand, often have vastly different expectations in terms of shedding body-fat. While a 9-12 percentage is classed as low for the average 20-30-year-old male, the average bodybuilder, in this bracket, would probably consider this to be unacceptably high, even as an off-season measurement.

Many bodybuilders, and general fitness exponents, keep their body-fat at around 8-10-percent (within striking distance of a competition, or simply to look good year round).

Despite being used for decades to measure body-fat (among the general population and pro athletes), the jury is still out on the efficiency and efficacy of caliper testing. Indeed, other methods such as hydrostatic weighing are thought to be superior. However, in most clinical or applied situations, underwater (hydrostatic) weighing is impractical.

This article, therefore, will analyze the different methods, and review the various types of caliper testing, to gain a broader perspective on how they can benefit those wanting to improve their health and body shape.

Why Measure Body-Fat?

The amount of body-fat a person carries can make a tremendous difference to their body shape and health. Because muscle tissue is more compact than fat, any deposition of fat, due to its tendency to balloon out, will cover a greater area than that of muscle. Fat also tends to congregate in specific places (primarily on the stomach in men and around the hips and buttocks in women). These factors affect overall body shape in a negative way, thus contributing to a disproportionate physique and unhealthy look.

In terms of health effects, excess fat can add stress to the joints, and cause postural problems. It is also linked to heart disease, stroke, diabetes and cancer.

Measuring body-fat is important for several reasons. To gain an indication of how much fat ones body is composed of serves as a starting point for a weight-loss program. Having a tangible result in the form of skin-fold measurements and/or percentages can help one to chart their progress over the duration of their weight-loss program. In fact, measuring body-fat regularly can serve to motivate and help an individual make any necessary modifications to their program.

What Is FatĀ & Why Do We Need It?

The most common fats in out body are the triglycerides. These come from oils, butter and other natural sources. Lipids are also the body's most concentrated source of energy, yielding around nine calories per gram as opposed to protein and carbohydrate, which contain about four. Lipids are stored as droplets in fats cells.

  1. Saturated fats are found in foods such as meats, lard, butter, cream, whole milk, coconut and palm oils. These are to be avoided, if possible, although there is some evidence to support their role in muscle development. Also, the food that contain these fats, also have vital nutrients that should not be forsaken in favor of complete abstinence from saturated fats.
  2. Monounsaturated fats are found in olive oil, peanut oil and canola oil. These fats are more beneficial than the saturated variety for maintaining health and wellness.
  3. Polyunsaturated fats Found in corn, sunflower, safflower and soybean oils. They contain beneficial omega-3 fatty acids, which are vital for health and well-being.

Calipers work by pulling subcutaneous fat (fat directly under the skin) away from the muscle with the tongs situated at their ends. Several predetermined sites are measured by a gauge that records the thickness of the pinch created by the tongs. An equation can be used to determine body-fat percentage, or the skin-fold thicknesses, on their own, can be used to gauge progress. The caliper testing method of body-fat measurement works on the notion that 50-percent of total body fat lies under the skin.


Abdominal: direction of fold is vertical, and is taken two centimeters to the side of the umbilicus.

Thigh: direction of fold is vertical, and is taken on the anterior aspect of thigh, midway between inguinal crease and proximal border of patella. Bodyweight should be shifted to the left foot throughout.


Waist: direction of fold is diagonal, and is taken above iliac crest along the anterior axillary line.

Thigh: direction of fold is vertical, and is taken on anterior aspect of thigh, midway between inguinal crease and proximal border of patella. Bodyweight should be shifted to the left foot throughout.

To Measure Correctly

  1. Find relevant sites on the right side of the body, before measuring. Mark these with a pen, and use a ruler to determine exactly where these sites are (for example, with triceps measure from the elbow to the designated site) for future reference.
  2. Lift a skin-fold firmly with thumb and index finger of left hand.
  3. Lift fold one-centimeter above the intended measuring site.
  4. Place jaws of the caliper perpendicular to the fold, one centre meter below the thumb and index finger.
  5. Read the caliper dial to the nearest 0.5 millimeter, about one or two seconds after the trigger has been released.
  6. Record measurement.
  7. Take three readings for each site, and average these to get the correct percentage reading. Remember, the result will only be an indication of body-fat level. The idea is to ensure it is as accurate an indication as possible.
  8. If the first two measurements vary by greater than one-millimeter, more should be taken until two measures vary by less than one-millimeter.

After summarizing the measurements taken from the sites listed above, a chart (developed by Jackson and Pollock) can be referred to, and body-fat percentage can be noted.

As mentioned earlier, readings can also be used to measure progress with having to calculate percentage of fat from the aforementioned equation, or any of the other 100-or-so available equations.

Tips For Using Calipers

  1. Have test carried out by a practicing professional to ensure accuracy
  2. Do not exercise beforehand, as this causes blood to travel to the skin, which increases skins thickness.
  3. Note measured sites exactly. When taking subsequent tests, accuracy depends on ones ability to recall the exact site. Measure with a ruler, or tape-measure. Do not guess.
  4. Ensure skin is dry and free of lotion or sweat.
  5. Measure body-fat at the same time of day, and under the same conditions each time. Tester error is the most common source of variation in measurements, so it is very important to ensure all the correct procedures are followed.
  6. Use good quality calipers. The most expensive calipers are generally the most reliable.
  7. Monitoring changes in skin-fold measurements, rather than a percentage (which is determined through a variety of equations) could prove to be a better option.
  8. Try to take reading within two-four seconds of applying calipers, as a delay could underestimate the skin-fold value.
  9. Completely release the spring handles of the caliper when taking measurement so that the full standard pressure of the jaws is applied to the soft tissues (subcutaneous fat) being measured.
  10. The best time to test is in the morning, before any form of training or activity.
  11. From time to time, take a more advanced test (such as hydrostatic weighing) and compare this to the caliper test results, to ensure these tests are accurate.
  12. Look directly at the caliper (not from a side-on angle) to get the bet possible result, and avoid measurement error.

How Low Is Too Low?

It is generally impossible to achieve a body-fat reading of below three-percent. Even under conditions of starvation, the body will maintain a degree of fat to support vital organs (essential fat). It is thought that about three-percent of a man's body-fat is essential.

Women need more essential fat for child bearing and other hormone related functions (the average woman's essential body-fat is around 12-percent). Essential fat is stored in the bone marrow, around the internal organs, and in the brain and spinal cord.

The average male (aged 20-30), according to statistical norms, will hold between 13-16 percent body-fat. Bodybuilders and other fitness adherents, on the other hand, tend to go much lower, but still generally do not go any lower than four-six-percent to achieve their best conditioning.

Caliper Options

The caliper measurement options reviewed below are generally regarded as the best available, as they are easy to use and scientifically tested. As body-fat measurement technology has progressed, calipers have also improved in a variety of ways.

Accu-Measure Personal Body-Fat Tester

Other types of calipers generally require the services of a qualified professional as they more complex to use, and, as a result, there is a greater possibility for error if self-testing.


  1. Measure within one-percent of gold-standard underwater weighing results.

  2. Easy to read measurements.

  3. Clinical proven accuracy.

  4. No dangerous electronic current or false readings.

  5. Easy to use.

  6. Fat loss can be monitored within seconds.

Fat-Track Gold, Body-Fat Tester

Recommended by publications, Oxygen, Physical, Shape, Ironman, Muscle & Fitness Hers, Max Sports & Fitness, American Health and Fitness, IDEA Personal Trainer, and Natural Muscle, Fat-track Gold could be the most effective caliper testing method yet.


  1. Uses the aforementioned Jackson-Pollack body density equations for determining body fat.

  2. Audible beep indicates correct pressure and measurement, ensuring accuracy.

  3. Self-calibrating for lifetime accurate measurements.

  4. Fitness rating indicator based on gender, age & body fat %.

  5. Stores 3 personal profiles.

  6. Statistical reports display-shows maximum and minimum readings at each measuring point.

Harpenden Skin-Fold Calipers

The Harpenden, valued at over $400, is touted as the most accurate skin-fold caliper in existence as it can be read to the nearest 0.1 mm, and can measure up to 55 mm.


  1. Highest quality.
  2. A standard research tool.

Lafayette Skin-Fold Calipers

The measurement range with these calipers is 0-100mm, double that of the Harpenden model. Lafayette's unique skin-fold design also has an adjustable zero-point which allows one to reset the pointer back to zero.


  1. Features floating tips for parallel measurements and a large, easy to read dial.
  2. Delivers a constant pressure of 10 gm/mm2 which is necessary for the Jackson-Pollock skin-fold equations.

Lange Calipers


  1. Accurate to + or - 1mm.
  2. Tips pivot automatically for parallel measurement.
  3. Easy to read scale up to 60 mm.
  4. All critical pivot points utilize low friction bearings.
  5. Spring loaded leavers provide a substantially constant standard pressure.

Example Of How Fat-Track Gold Calipers Work

Subject: Natalie Robson. Gender: Female. Age: 29. Height: 171cms. Weight: 50kg.

Results showed a very low percentage of body-fat, according to the universally used Jackson and Pollock table.

Calipers, According To Those In The Know

To gauge the usefulness of calipers as a fitness testing tool, several experts in their respective fields were contacted, and their opinions asked.

Rob Thoburn: Bodybuilding Researcher & Scientific Adviser

With the above in mind, any pair of calipers will work fine. The greatest source of variability comes from how you use the calipers, who takes your measurements, what measurement sites you use (you should measure at the same body location(s) all the time), etc.

The more these variables are held constant, the more likely you are to see a change in the variable of interest, your body fat level. I hope this sheds some useful insight, David. Thanks for considering my opinion!"

Determining BMI

For example, a person who weighs 220 pounds and is 6 feet 3 inches tall has a BMI of 27.5.

BMI is only a correlate, and not a direct measure, as it does not factor in gender, age and level of muscularity. A bodybuilder like Lee Priest, for example, would register as obese despite being shredded at 6-percent body-fat, as he is classed as short and he does hold a lot of muscle weight (weight is weight as far as the BMI is concerned; it does not discriminate between fat and muscle).

Lee's BMI would be way off the chart, despite low body-fat levels and loads of muscle. Caliper testing is widely recognised as being a superior measure of body-fat compared with BMI testing.

Hydrostatic Weighing

Before submersion in a water tank, one is weighed. Submersion in water occurs next, in which subject is weighed again. This procedure works on the premise that bone and muscles have a greater density than water, while fat is of a lower density than water.

All of this means a person with more lean body mass will weigh more in water than a person with less lean body mass. This person will therefore have a higher body density and a lower body fat percentage. Once the bodyweight of the subject is taken, the body fat percentage is calculated using a the Siri formula:

BF% = (4.57 / DB) - 4.142) x 100

Melissa Coates: Pro Bodybuilder

The Mirror

Shawn Ray: Pro Bodybuilder

Simply because my body fat was not something I was preoccupied with like body measurements. Neither of them factored into the judging criteria on stage, so I simply did not want to waste my energy measuring something that did play a part in what the judge was judging. I focused on the "Mirror" my entire career.

The judges, judged my appearance not my body fat, hence no hang ups on percentages or measurements."


Determining approximate body-fat percentage is a very useful way in which to gauge physical progress. Skin-fold calipers have been used for years to help determine body-fat levels, and many trainers and athletes believe they provide an excellent means in which to self assess and monitor.

Losing excess body-fat (for health and cosmetic reasons) is, in many ways, a great idea. Monitoring ongoing fat-loss is crucial if weight loss goals are to be met, and using calipers may be the best way to do this.


  1. American Council on Exercise.(1991). Personal Trainer Manual. ACE: USA.* Jackson A.S., & Pollack, M.L.(1985).
  2. Practical assessment of body composition. The Physician and Sports Medicine. May, 76-90.* Sport Fitness Adviser.(2005).
  3. How to use Body Fat Calipers and Make Them More Reliable. [Online]*
  4. Weight loss resources.(2005). Body Fat Percentage. [Online]

About the Author

David Robson

David Robson

As an active martial artist, bodybuilder and accredited personal trainer, David employs the latest cutting edge research to enhance his own progress.

View all articles by this author