How To Check Accuracy of Bathroom Scale and How Does It Work

This site contains affiliate links to products. We may receive a commission for purchases made through these links.

Keeping track of your weight isn’t just about having a nice figure.

Most of the time, it is about maintaining good overall health, so having a reliable bathroom scale is essential.

A good scale can last a long time if properly maintained for its job.

It can provide accurate measurements and consistently give stable weight readings.

However, how would you know if your scale is malfunctioning?

We cannot emphasize enough the importance of learning how to check accuracy of bathroom scales.

Hence, we are here to help by giving you tips on how to do it.

Types of Bathroom Scales and How They Work

When you purchase a bathroom scale, you automatically assume and trust its reliability.

With all the numerous models promising to deliver the most accurate results in the market, gauging its accuracy can be challenging.

That is why understanding how bathroom scales work is essential.

It can give you an edge and help you determine whether it is working correctly or not.

Below are some pieces of information about the two common types of bathroom scales.

We also prepared an explanation of how they work and the possible problems each can have.

Mechanical Bathroom Scales

Mechanical scales utilize a lever cross arrangement to support your weight and distribute it evenly across the scale.

When you press down on these levers, it pushes down on a central spring.

The spring uses complex mechanical arrangements to turn the dial that tells the weight.

It uses a mathematical ratio between the point where your weight presses on the levers and where its fulcrum is.

This comes with its design, so it can be small enough to fit in a bathroom.

It utilizes a spring to give the pull and resistance that the dial needs.

That said, there are different ways this can cause inaccuracy issues.

The trouble usually starts when it reduces your weight through ratios because it can miss small weight fluctuations.

The display may show a margin of error because it utilizes a physical radial dial.

This can also happen when the spring isn’t heavy-duty, or there’s improper lever placement.

In some cases, this happens because the scale is old.

With any mechanical arrangement, proper calibration is vital for an accurate reading.

That’s why industrial scales have strict tolerances and a series of thorough overviews of their manufacturing processes.

They also have plenty of testing to ensure accuracy.

Mechanical scales have an upper weight limit they can accurately read.

The readings can be less accurate if you fall beyond the limit, typically around 250 pounds.

Digital Bathroom Scales

Digital bathroom scales work differently from mechanical scales and have been used since the late 1930s.

They’re generally considered more accurate and reliable than mechanical ones.

A genuinely high-tolerance digital scale can be highly accurate, but a low-quality one can be as fickle as a mechanical box.

These scales start the reading with a small electronic item referred to as a strain gauge.

They have an arrayed layer of metallic foil sitting on a load cell that includes a transducer and a sensor.

As you step on the scale, your weight gets evenly distributed across the surface and presses down the strain gauge. 

It converts weight into an electrical signal that is then measured.

Simultaneously, the circuits in the device convert the measurement into an accurate weight reading on the scale.

This allows the digital scale to be reliable and more compact than a mechanical scale.

When calibrated correctly, electronic scales are accurate and reliable.

There are several methods included in the instructions on how to “zero out” digital scales.

Zeroing the scale gives the scale an idea of what level of the signal, or lack thereof, should be considered “zero”. 

After all, the scale’s surface has a weight of its own that is necessary accounted for.

In general, the circuitry on a digital scale will be reliable, among others.

Still, we must factor in low-quality digital scales, which may deliver inaccurate readings because of quality issues.

The bottom line is, the common points of inaccuracy for digital scales are in the parts themselves.

Over time, circuits degrade, the load gauge crack and fail, and parts wear out.

how to check accuracy of bathroom scale

How To Check Accuracy of Bathroom Scales

After understanding how each bathroom scale works, you are now ready to check for its accuracy.

Any reading from an unreliable weighing scale will only cause you more harm and give you false expectations.

Hence, make sure to practice the following steps to check for your bathroom scale’s accuracy from time to time.

Step #1: Zero It Out

When checking for your scale’s accuracy, make sure to zero it out.

This step is essential for determining the scale’s accuracy, but it will depend on the type of scale that you have.

You can press the scale down with your hand and lift it if you currently have an analog bathroom scale.

You can use the turning wheel situated at the scale’s lower part or adjacent to the dial if it doesn’t level out to zero.

Doing so will let you move the scale’s dial until you zero it out while at rest.

After doing so, make sure to re-test it to confirm that you could do it properly.

As for digital scales, you can follow the same steps.

The only exception is that you use a digital button for balancing and not a turning wheel.

Step #2a: Weigh an Object

You can resort to weighing an object that is familiar to you.

That means acquiring an object that you already know the weight of.

When choosing one, make sure that it is big enough to be registered on the scale.

Get an item that you can carry easily onto the scale for convenience.

If you are clueless about what to use, you can try using a bag of sugar or flour. 

These are usually available in pre-weighed packaging, so all you have to do is compare it to your scale’s reading. 

If this is unavailable, you can use hand weights.

These are fairly convenient because they usually have their weight written on each side.

Step #2b: Reweigh the Object

Another method that you can do would be to reweigh an object several times.

Since you have weighed the bag of sugar or flour in the previous step, you do the same thing here, except you repeat the process a couple of times.

Once the scale is zeroed out, place the item onto it and record its weight.

Remove it, let the weighing scale zero out again and repeat the process.

It is suggested that you do this at least five or an odd number of times to get results.

From there, you will be able to tell if there is inaccuracy because if a scale isn’t working well, you will have varied readings each time.

Step #2c: Weigh Two Things

You can further check for accuracy by weighing two things together.

It will give you more weight to measure and test the scale’s accuracy and weight distribution.

You can do this by placing one of the two items on the scale first and recording its weight.

After this, you do the same process to the second item and record its weight too.

After doing so, you move on to placing both items on the weighing scale and recording their combined weight.

Once you get the results, get the sum of the individual recorded weights of the items.

From there, you should compare it to the reading of the items together in the scale.

You should have the same results because having different values indicates an inaccuracy of the scale.

Step #2d: Measure Your Body Weight

Another good strategy to check your bathroom scale’s accuracy is by measuring yourself while holding something.

You do this by stepping onto the scale and recording your weight.

Then weigh the item you are to hold and record its weight with the same unit, such as pounds.

Once you have a separate recording of your weight and the item, you can then step on the weighing scale while holding it.

Check on the results and compare them to the sum of the item and your weight. 

It should give you the same value because having results that don’t match indicates inaccuracy in your scale.

What You Should Do if Your Scale is Inaccurate

You can try a few things if your scale has been tested and found to be inaccurate.

You can try moving it to a new location. 

Your bathroom’s surface may be a little slanted, resulting in inaccurate results.

In this case, it is best if you have it repaired or replaced.


A lot of people use bathroom scales to measure their weight for several reasons.

Accuracy is crucial for fitness, weight tracking relative to a health condition, or recording gains or losses.

Hence, when choosing a bathroom scale, always go for quality, durability, and accuracy.

Make sure you also understand how your specific weighing scale works by reading its manual.

Also, regularly check the accuracy of your bathroom scale. After all, the steps on how to check accuracy of bathroom scales are simple.

Special offer for our visitors

Get your "Choosing the Perfect Weighing Scale" Free Guide

We will never send you spam. By signing up for this you agree with our privacy policy and to receive regular updates via email in regards to industry news and promotions