When to Perform Scale Calibration and Why It’s Important

three men examining a manufacturing process on their way to perform a scale calibration procedure

Reliance on scales and balances for trade or commerce dates back thousands of years. Like many of the scales used today, the first weighing devices were fairly simple contraptions that determined the weight of goods on one side by adding counterbalancing stones to the other. 

Today’s scales and balances are more sophisticated, though, capable of detecting the smallest deviation in weight down to fractions of a gram. Balances and scales are now an aspect of daily life with applications everywhere from manufacturing and shipping to laboratory research or medicine. 

Read on to learn everything you need to know about weight scale calibration and why it’s so essential in various commercial, industrial, or healthcare arenas.

What is Scale Calibration and Why Is It Important?

Scale calibration is the process of ensuring that a scale is reading accurately. It is an essential step for business owners who rely on scale accuracy for things like inventory weighing, livestock weight, or product count. Scale accuracy becomes especially important when working with laboratory equipment and precise measurements

No matter what type of scale or what industry it’s being used in, having a properly calibrated scale prevents weighing mistakes which can cost extra time and money. 

No business owner has time for setbacks—so it’s best to educate yourself on how often a scale should be calibrated and how the process works.

Why Do Scales Require Calibration?

Aside from the fact that industrial scales and laboratory scales endure normal wear and tear from everyday use, there are various reasons a scale would require servicing. Even the slightest shifts, vibrations, or even temperature changes can create unstable readings over time.

If a scale is moved from one location to another, it will likely need to be calibrated before use. This is because gravitational force will vary slightly at different locations around the world. In addition, some scales, like those used in laboratory settings, are extremely sensitive to environmental changes, so moving these scales without calibrating them properly is especially likely to result in inaccurate measurements.

Potential Consequences of Neglecting to Calibrate Your Scales

Calibration is vital, and failing to properly calibrate a scale or balance can cause the device to provide false measurements, leading to negative outcomes. 

Inaccurate weight readings, for instance, can negatively impact businesses that rely on scales or balances to estimate shipping costs, with unexpected charges for overweight products or excess money spent on underweight products potentially adding up to a large sum of money by the end of the year. 

For manufacturing or laboratory environments that must adhere to strict compliance standards, a malfunctioning scale or balance can come with even more severe consequences, such as steep fines, poor production quality, and disruptions to operations. 

Inaccurate scale readings can also cause problems in medical environments where carefully tracking a patient’s weight is critical to diagnosis and treatment.

How Does Scale Calibration Work?

The process of scale calibration begins with a certified mass being placed on the scale and the reading is recorded. Then it’s checked against standards or within tolerance for accuracy to determine if any adjustments are required. If the results are within the calibration tolerance standards, then the scale will not need any adjustment. However, when these don’t match, necessary service may need to be done to get the scale in working order again.

PRO TIP: When calibrating your scale, it’s important to use high-quality calibration weights that are certified and traceable to a national or international standard. This will ensure that the calibrations themselves are as accurate as possible. 

What Is Calibration Tolerance and How Is It Calculated?

During the calibration process, the accuracy of a scale is determined by its calibration tolerance. This is the amount of deviation that is allowed between the actual weight and the displayed weight on the scale. 

The calibration tolerance is usually expressed in percentage terms, such as +/- 0.2%.To calculate the calibration tolerance, you need to know the readability of the scale and the weight resolution of the scale. 

  • The readability of a scale is the smallest increment that can be displayed on the scale. 
  • The weight resolution is the smallest change in weight that can be detected by the scale.

The calibration tolerance can be calculated using this formula: Calibration Tolerance = Readability / (Weight Resolution x 100)

How to Calculate Scale Calibration Tolerance
Calibration Tolerance = Readability / (Weight Resolution x 100)

For example, if a scale has a readability of 0.1 g and a weight resolution of 0.01 g, the calibration tolerance would be +/- 0.2%. This means that the actual weight could be up to 0.2% more or less than the displayed weight on the scale.

5 Basic Steps to Calibrate Your Scale:

It’s likely time to calibrate if you notice your weighing device is not performing as well as it should be or if it has not been calibrated for over a year.

Most scales will come with specific instructions on how to calibrate them and how often it is necessary. However, there are some general steps you can follow to calibrate almost any scale:

  1. Start with an empty scale and zero it out. 
  2. Place a known weight on the scale and adjust the display until it matches the known weight. 
  3. Remove the known weight and check that the scale returns to zero. 
  4. Repeat steps 2 and 3 with different weights to calibrate the scale over a range of weights. 
  5. Check the sensitivity of the load cell by slowly adding weight to the scale and observing how the display changes. The display should change smoothly and evenly as weight is added. If it doesn’t, the load cell may need to be adjusted.

PRO TIP: Make sure that the weight is centered on the platform and that there is no debris on the platform or sensors.

If you notice that the scale is not returning to zero when empty, or that the display is not changing smoothly as weight is added, calibrating the scale may fix the problem. 

This is a relatively simple process that can be done by following the manufacturer’s instructions.  If you’re not sure how often your particular type of scale should be calibrated or if you have questions on how to perform the calibration correctly, check with the manufacturer or a professional to get the best advice.

The Difference Between Internal and External Calibration

Some of today’s higher-end scales and balances contain an internal calibration system that can effectively self-test the accuracy of weight readouts. Some weighing devices will even allow users to pre-schedule automated calibrations that will occur at various intervals as needed. Scales or balances that can perform internal calibration are often more expensive, though, and are most commonly used in laboratory settings.

For external calibration, a set of weights are needed to determine the accuracy of the device. This form of calibration is usually performed by a trained professional for a fee. So, if your business relies on scales and uses them multiple times daily, it may be worth it to invest in models that can perform calibration internally to save time and money in the long run.

How Often Should My Scale Be Calibrated?

For any business owner, keeping track of inventory is key to success. For manufacturers, this means calibrating scales often to ensure accurate readings. This is an important step that should not be skipped.

Calibrating often can help you catch any issues before the scale begins to drift so you can make corrections before the weight readings become inaccurate and impact your business’ bottom line.

But how often should you calibrate your scale? And what factors come into play when making that decision? Depending on the model and brand of scale or balance you have, calibration needs will vary. 

There is no one definitive answer as to how often you should calibrate your scale. Depending on the make and model, as well as how often it is used and what it is used for, calibrating every month, every six months, or every year may be necessary. Some scales may even require calibration weekly to ensure measurements are accurate. 

PRO TIP: In general, There are many factors that determine when you should calibrate your scale. But if you’re completely unsure of where to start, calibrating your scale at least once a year is a good rule of thumb. 

6 Tips for Keeping your Scale or Balance in Good Working Condition

6 tips for maintaining your scale or balance infographic
6 tips for maintaining your scale or balance infographic

The accuracy and expected service life of a scale or balance will largely depend on how well the device is maintained. Using the scale improperly or failing to keep up with preventative maintenance can eventually lead to various types of malfunctions. 

Follow these simple tips to keep your scale in optimal shape.

1. Clean the Scale Regularly

Eventually, dirt and grime build up on a scale’s components, which can lead to malfunctions. This is also true for lab scales that are weighing chemicals and other hazardous materials.

If you’re cleaning a digital scale or a lab balance your first step is to make sure the device is turned off before proceeding. Then, remove the load plate from the scale and clean the surface thoroughly with a slightly damp cloth. Next, gently wipe down the rest of the scale to remove any remaining debris. If there’s any difficulty removing dust or other contaminants, you can add a small amount of vinegar to the water.

2. Avoid Dropping Heavy Weights on the Scale Suddenly

Scales are sensitive devices, and the sudden shock of weight dropped onto the load plate can potentially cause damage. Placing items gently on the scale, in contrast, will help ensure that the device continues to work properly in between calibrations. 

Also, avoid dropping the scale on the ground or moving the scale around more than necessary. If you’re storing a scale for later use, make sure there are no other items stacked on top of it.

3. Keep Water and Moisture Away from the Scale’s Internal Components

Modern scales are built for use in dry, clean environments. Never submerge a scale in water or allow moisture to seep into the internal electronics. Humid conditions can also wreak havoc on scales and balances, so it’s important to maintain a climate-controlled environment in areas where weighing devices are used. 

Luckily, there are scales on the market today that are designed to ensure that load cells are completely insulated from their external environment. If you’re concerned about moisture damaging the scales at your business, simply purchase one of these hermetically sealed weighing devices.

4. Always Ensure your Scale or Balance Rests on a Level Surface

Scales and balances are designed to operate on a flat, level surface. Any wobbling can cause weight to be unevenly distributed across the load plate, and this can damage the device. 

Additionally, avoid using a scale placed on a carpet or a rug, as soft surfaces may interfere with accurate weight readings. Even slightly pliable surfaces like vinyl flooring can affect a scale or balance, so always place weighing devices on solid surfaces like wood flooring or ceramic tiles.

5. Routinely Inspect your Scale or Balance

Visually inspecting your scale from time is essential to ensure that the device continues to operate effectively. In several industries, scale inspection is mandatory, and these industries must meet various federal and/or state compliance standards. 

If you notice any visual signs of wear or indications that your scale has been damaged, the device should be carefully examined by a trained professional for repair and recalibration.

6. Never Apply Weight to the Scale Beyond Its Tolerance Limit

Different scales are designed to withstand weight thresholds specific to the intended applications of the device. Exceeding these tolerance levels can harm weighing devices, contributing to inaccurate weight measurements or causing irreversible damage. 

To be safe, it’s always best to use scales with a weighing capacity well above even the heaviest item you’re weighing.

American Scale Can Help You Get Back to Business

Happy engineers stacking hands while working at a manufacturing warehouse

At American Scale, we provide our clients with reliable scale services and calibration for virtually any weighing device on the market today. We are an accredited service provider, and our technicians follow all the latest compliance guidelines and regulations regarding scale repair or calibration. 
We offer a wide variety of scale options and services to meet your needs. Contact us today to learn more about how we can help you calibrate your scale and get back to focusing on what you do best—running your business.