Test Weights Explained: Your Ultimate Guide

What are test/calibration weights?

Test weights are used to check weighing instruments and establish whether you need to calibrate your scales. If you regularly use scales in an industry environment, such as pharmaceuticals, retail, or production, you’ll benefit from maintaining accuracy with the help of calibration weights. These weights are available in a variety of sizes and weights, all standardised to ensure maximum precision…

In any industry relying on precision weighing, maintaining accuracy is a no brainer. But just how exactly do you ensure your scales run as accurately as possible to avoid any costly mistakes?
Enter: test weights. 

Test weights are used to calibrate scales, to ensure that you’re getting precise, accurate results every time you weigh products. These standardised weights are manufactured to strict tolerances and are a must for industries in which accuracy is non-negotiable. 

Using them is simple – you weigh them with scales set to zero and check that the weight shown on the display is what you know the test weight weighs (they’re standardised).

If you’re in doubt about the effectiveness of your scales, test weights can either put your mind at ease or alert you to a problem, allowing you to either fix the issue or replace the faulty scales. Test weights come in various sizes, and classes, so establish the best one for your needs before beginning the procurement process. 

Why Are Test Weights Important?

If you’re not currently having issues (that you know of) with your scales or balances, you’re probably wondering why test weights are so crucial. Having test weights to hand helps with the following:

• Assured accuracy. Inaccurate readings can jeopardise fair retail transactions and your company’s integrity. In the worst-case scenario, such as laboratories, having a measurement even slightly out can render the end product useless. With test weights, you can reduce the risk of errors.
• Regulatory compliance. In many sectors, using accurate scales isn’t just a bonus – it’s actually required. Using test weights and calibration to ensure accuracy can help your business become more legally compliant. In some scenarios, routine calibration with test weights is actually mandatory. 
• Consistency. Regular verification of scales prevents discrepancies that could affect business operations and consumer trust – put simply, it makes your business more reputable and reliable.  
• Cost savings. Believe it or not, more reliable measurements can actual reduce costs and financial wastage – especially in retail environments!

Who Needs calibration Weights?

Unlike scales or balances, test weights aren’t specific to a certain industry or type of business. Essentially, if precision and accuracy are important to you, you’ll probably benefit from test weights. 

Some of the most common industries for test weights and calibration include laboratories, manufacturing, retail, the food and beverage industry, and logistics. There are different classes of calibration weights for purchase, too.

Here are the more commonly used classes and the readability of the scales/balances or application they can be used to test:

M3 – 10g and above (general weighing tests)
M1 – 0.01-1g and above (general scale uses)
F1 – 0.001g/1mg and above (Precision Balance)
E2 – 0.01mg and above (Semi-Micro Balance)
E1 – 0.001mg and above (Micro Balance)

There are more classes but these are the most common. We generally see E1-2 or M1-3 sold the most. M1 calibration weights are generally used the most, additional to weighing they can be even used in structural tests like bridge testing, for formula 1 or E or even drone capacity tests. E1 or E2 tests weights are usually used in labs.

How to Use Test Weights to Check if You Need Calibration

Need test weights to ensure accuracy for your scales and balances? Here’s the basic step-by-step process.

1. Clean the scale and calibration weights. That way, your results won’t be affected by the build-up of dirt and dust. 
2. Ensure the scale is on an even surface for maximum accuracy
3. Check the scale is displaying zero before you add any weight. 
4. Place the test weight on the scale, ensuring it’s placed in the centre and in the middle of the four corners (see below) to check eccentricity which in laymens term means distribution between the load cells.
5. Compare the weight of the test weight and the scale’s display. If there’s a discrepancy between the weight it’s displaying and what you know the test weight weighs, this shows your scales need calibrating.  
6. If needed, adjust the scales as per manufacturer instructions. 
7. Record test weight data in case it’s needed by your colleagues in the future. 

Frequently Asked Questions

What are Calibration weights used for?

Calibration weights are used to calibrate weighing scales. If you’re worried your scales aren’t displaying weights accurately, using test weights can be an easy way to either get reassurance or address a problem with your scales. 

Industries such as pharmaceuticals, food production, and logistics rely on test weights to maintain precision in their weighing processes. Even if your business isn’t in one of these industries, you can benefit from them regardless. 

Why does test weight matter?

In many industries, accuracy matters. Calibration weights allow you to calibrate electronic scales to ensure that the scales you’re using are providing you with accurate results. Test weights can help prevent financial losses and ensure compliance with industry standards. 

How is test weight calculated?

Calibration weights are carefully manufactured to specific tolerances and calibrated against high-precision reference standards, so whichever type you choose, you can rest assured they’ll work as they should. Remember to purchase calibration weights in line with the readability of your scale. 

Scales and Balances is home to a wide range of test weights, so whether you’re using retail scales or industrial weighing scales, you can enjoy peace of mind that they’re working accurately. For help choosing the right set for you, speak to an expert.