In any industry where measurement is key, from a pharmaceutical lab to a busy shipping depot, you’re relying a lot on the accuracy of your weighing scales.

 But how do you know if your scale is actually telling the truth?

The answer lies in calibration weights. Often referred to as test weights, these are the gold standard for maintaining the integrity of your weighing equipment.

In this article we take a closer look at the purpose of scale calibration weights and how to choose the right weights for your setting.

What Exactly is a Calibration Weight?

In simple terms, a calibration weight is your on-site benchmark. Its mass is precisely known and certified, so it acts as a fixed point of reference that tells you exactly how much your scale is ‘drifting’.

By placing a certified 1kg weight on your scale, you aren't just weighing an object, you’re auditing the scale's performance. If the scale reads 1.002kg, you know immediately that your equipment requires adjustment.

Without routine checks using certified test weights, ‘scale drift’ can occur over time due to environmental changes, mechanical wear or accidental damage.

Which Calibration Weights Do You Need?

Choosing the right weight isn't a one-size-fits-all process. To find the perfect match for your laboratory balance or industrial scale, consider these three factors:

1. Matching the Weight to Your Scale’s Sensitivity

 The most critical factor in choosing a weight is the readability of your scale. 

For high-precision lab work, our F1 Calibration Weights are the ideal choice. These are specifically engineered for professional balances with a division size between 0.1mg and 1mg.

You should have enough weight to test your scale to its full capacity, or at least to the highest weight you typically process. We offer a wide size range to facilitate this: 

• Milligram Weights: Essential for micro-measurements and analytical balances. Our milligram weights are crafted from aluminium or 304 stainless steel and come in protective polygonal sheets to prevent damage.
• Gram and Kilogram Weights: For bench and floor scales, we provide knob-shaped weights ranging from a single gram up to 20kg. These are fabricated from premium Troemner Alloy 8 or 316 Stainless Steel, ensuring they remain corrosion-resistant even in busy industrial settings.

For many businesses, a calibration weight set is the smart investment. It provides a variety of increments, allowing you to check accuracy at the bottom, middle, and top of the scale’s range rather than just a single point check.

2. The Depth of the Test

 How thoroughly do you need to check your equipment?

• Routine Accuracy Checks: For daily or weekly spot checks, you might only need weights that cover key points, such as 50% or 100% of the scale's capacity.
• Full Calibration & Adjustment: If you’re performing a full system reset or preparing for an audit, you will need a comprehensive set of weights that cover the entire range, ensuring accuracy at every level.

3. Understanding Accuracy Classes (OIML)

Calibration weights are categorised into classes based on their tolerance levels. Using a heavy industrial weight to test a sensitive lab balance will result in poor data.

• E Class: High-precision weights for analytical balances.
• F Class: For precision laboratory scales.
• M Class: Robust weights for industrial and commercial scales.

We always recommend using weights that come with an OIML certificate or a UKAS calibration certificate. This ensures the weight is traceable to national standards, which is essential for quality management and legal compliance. 

The Easiest Way to Get it Right

At Quality Scales, we take the guesswork out of the process.

The easiest way to find exactly what you need is to talk to our experts. By simply telling us the type of scale you have, its maximum capacity, and its readability (the smallest increment it displays), we can recommend the precise weight class and size range for your specific environment.

Don't leave your accuracy to chance. Take a look at our range of calibration weights or get in touch to discuss your needs. We’d be happy to chat through the options!