Last Updated on July 28, 2021
Owning and using a bathroom scale is fairly commonplace, especially if you like to track your health and fitness. However, have you ever stopped to wonder how a bathroom scale works? Do they measure mass in addition to measuring weight, and what’s the difference?
Also, bathroom scales can vary greatly in accuracy, so which ones work best? This article answers the question of what do bathroom scales measure and explores how they can help you lose weight and achieve your health goals with greater accuracy.
Bathroom Scale Basics Explained
Let’s take a look at the basics of bathroom scales to understand them better.
How Do Bathroom Scales Work?
Different types of bathroom scales work differently, but for the most part, scales measure body weight or mass through force. When you step on a scale, the force applied is used to measure weight.
More advanced scales like analyser and smart scales used advanced technologies to measure more than just weight mass using various techniques. Could you keep reading to find out what we mean?
What Is Measured?
In the most basic terms, a scale is a weighing machine that is used to measure force by way of mass. Some scales can also be used for measuring body fat and water percentage, BMI, metabolic rate, and even bone or muscle mass. The more advanced the scale, the more it will be able to measure with accuracy.
Mass and Weight
Kilograms are a measurement of mass, not force. So, if scales measure force, why don’t they display mass? This is a bit technical but stick with us.
Mass is a representation of the amount of matter contained in a particular object. Weight is the measurement of force on our body caused by the pull of gravity on our mass. More force equals more mass. The pull force is measured in mass. Then, the scale can convert mass, or Newtons to kilograms, thanks to the direct relationship between mass and weight.
What Do the Different Types of Scales Measure?
If you are looking for a new bathroom scale or weighing machine, you have quite a few options to consider. The following sections break down the different types and explain how and what they measure.
A mechanical bathroom scale, also known as a spring scale, measures the force applied to the surface via an internal spring. When force is applied to the mechanical scale inside, the spring compresses. The scale then measures the change in the length of the spring to determine the force applied. They measure bodyweight only, not body water or how much fat you have.
Mechanical scales are easy to use, and no batteries are required. They can last for many years and often have a max capacity of around 21 stone or 136kg, which is somewhat less than the max capacity found with digital scales. They display measurements in 1kg weight increments. Mechanical scales are not as precise as other options but are good for occasional use.
A digital bathroom scale also measures weight by way of force. Digital scales display weight via an easy-to-read LED screen in weight increments of 0.1kg or 0.05kg depending on the specific model of scale. The typical digital scale can measure a weight range reaching as high as 200 to 250kg and allows you to choose between kg or lb units.
More advanced digital scales can even track your weight loss progress. This type of scale is good for regular tracking of your weight with more precise measurements.
Analyser scales use a Bioelectrical Impedance Analysis (BIA) system to measure impedance and weight accurately. A small electrical current is activated when you step on the scale, and it shoots up your leg and pelvis to measure the amount of resistance caused by your body fat.
Then, the scale measures and analyses the resistance as the current travels back down your other leg to the scale’s sensors. A greater resistance equals higher fat. This is because fat contains less water and is denser than muscle allowing the scale to estimate the quantity of water and fat in your body.
Analyser scales can display various measurements, including body fat percentage, weight, muscle mass, body water percentage, BMI, bone mass, and BMR. They provide a more comprehensive measurement of your body composition so you can understand your overall health on a deeper level.
These scales are good for athletes or anyone embarking on a new exercise program or diet because they can consider the fact that you may be losing fat but gaining muscle mass.
However, keep in mind that an analyser scale is highly affected by the amount of water in your body, so a recent shower, the time of day, your fluid intake, or even your menstrual cycle could affect the results by as much as 5%.
A smart scale can be similar to a digital scale or an analyser scale but uses a Bluetooth connection to measure your results on a phone or other smart device accurately. They allow you to easily track your current weight, actual weight, body composition, blood pressure and even offer healthy goals. A smart scale will often give you the most detailed analysis of your overall health.
Other Health and Fitness Considerations
When using bathroom scales, there are also health and fitness factors that you need to consider.
Body Mass Index (BMI) Vs Body Fat
ACCORDING TO MEDICAL PROFESSIONALS, the BMI index takes weight and height into account to determine whether a person is underweight, overweight, or obese. Your BMI measurement aims to tell you if you are a healthy weight for your height. You can easily calculate your BMI without a scale using a simple equation, and while this can be a good indicator of your health and fitness status, it is not entirely accurate.
BMI does not measure fat and does not take into account muscle mass or body fat percentage. Instead, it is based on a general weight range based on your height. So, if you are losing body fat but gaining muscle mass or lean tissue, your BMI may stay the same because you have the same mass overall.
A BMI measurement does not do a good job of interpreting lean body mass or extra muscle mass. This means bodybuilders could show up as overweight or obese, and avid runners with lots of lean mass may show up as underweight.
What Are the Benefits and Disadvantages of Body Fat Scales?
Body fat scales are an excellent way to keep a record of your weight loss journey or overall health and wellness from the convenience of your own home. However, they are not always entirely accurate.
Accuracy can be affected by several factors like biological sex and pregnancy, where your body typically stores fat, age, height, or regular resistance and endurance training. So while you may still weigh the same amount for an extended period of time, your body composition may be changing.
One of the main drawbacks to a body fat scale is that it does not tell you where fat is being stored on your body, only the overall percentage. Knowing where fat is stored can be important because the extra weight in your midsection can increase your risk for heart disease and other health conditions.
However, all in all, body fat scales can still help you in keeping tabs if your diet or workout routine is working or not. They may not always be accurate, but you will have a pretty good idea of your progress.
How Else Can You Measure Body Fat?
Here are some other ways how you can measure your body fat:
Measure Your Waist
A tape measure is good for measuring fat stored in the midsection. As we discussed, this can be important when assessing the risk for health conditions such as type 2 diabetes, heart disease, or fatty liver disease. Measuring your waist can be used, and body fat scale measurements to determine where weight is being stored.
When you are using this method, measure in line with your belly button, as a general rule of thumb, a measurement of more than 16cm for men or more than 14cm for women is considered to be obese.
Calipers or Pinchers
Calipers pinch fat on your body to determine the overall percentage. They can be used to pinch fat around your hips, waist, upper arms, or thighs. Unfortunately, the accuracy of this method varies greatly based on the person using the pinchers and the quality of the pinchers themselves.
DEXA or dual-energy x-ray absorptiometry scan analyses bone mass and measures the bone density of an individual. During a DEXA scan, you lie on a table for about 10 minutes while the scanner analyses your body composition.
Measuring bone mineral density in this way is often used to make an osteoporosis diagnosis but can also be used to take an accurate muscle and body fat measurement. It can even show where fat is concentrated. This option is highly accurate but often expensive and requires a facility that offers this type of measurement.
Underwater Weight Test
An underwater weight test or hydrodensitometry test uses buoyancy to measure your body fat. You submerge yourself in a water tank, and the amount of water displaced is used to calculate body density and body fat.
This method is not widely used because it can be hard to find a centre capable of this kind of measurement, but it may be the most accurate method.
A bod pod uses plethysmography (ADP) or air displacement to measure body fat in simpler terms. You stand inside the pod for a couple of minutes while it works its magic. They can be highly accurate, but you must remain very still and control your breathing while inside.
In addition, your level of hydration can affect the accuracy of the results, so it’s best to follow the highly specialised instructions. Bod pods are often found in gyms, and some medical facilitates.
Scale Reading Made Easy
After reading the article, you may be surprised at all that scales are capable of. While scales are not designed to provide medical advice, the right scale is capable of measuring much more than just your mass or weight. As we learned, some scales can measure BMI, water percentage, fat percentage, muscle mass, and more to give you a comprehensive analysis of your body composition. With this in mind, what kind of scale will serve you best?
Let us know what you think in the comments below.