Understanding Calibration Weights

If you’re looking for more information on calibration weights and what they are used for, read our guide below to learn all about them…

Calibration weights are fixed weights that are used as a guide for calibrating and testing your weighing equipment. They are the ideal solution for making sure your weighing scales are measuring items accurately and are used to calibrate weighing scales. Your calibration provider will use standardised test weights to determine the accuracy of your weighing equipment.

If your business is looking to undertake scale calibration internally, you’ll need to buy calibration weights to make sure this is done properly to ensure consistency and quality in your production process.

Polished Brass Cylinder Weights


Click the button below to browse our range of test weights, with cast iron and brass options available.


There are a range of different weights on the market, each useful for different types of applications. Variations include:

  • Cylindrical Weights
  • Bar Weights
  • Hooked Weights
  • Slotted Disk Weights
  • Tab/Leaf Weights

Cast Iron Bar Weight

Each has their own place and application. For example, polished metal cylinder weights are useful for long term, high accuracy calibration where smaller margins are being measured. Cast iron bar weights, however, are ideal for higher capacity testing on platform scales that might be weighing items of up to 50kg or more.

Calibration service providers will have complete sets of weights to make sure they can calibrate all kinds of weighing equipment. When performing calibrations internally, however, it’s important to make sure you have the correct weights on hand for effective testing – including the type of weight and the class of accuracy like M1, F1, and E2, which we explain in more detail below.


Classes of accuracy refers to the accuracy of the calibration weights themselves. These classes are determined alongside weighing tolerances i.e. the amount of permissible errors either above or under the target weight. In this instance, tolerances are defined by the International Organisation of Legal Metrology’s (OIML) R 111-1 recommendations.

Different types of weighing instruments might require different classes, depending on how precise the measurements need to be. A laboratory balance, for example, would need to measure finer items to a high precision, so would likely require a weight with an accuracy class of E2 and higher. A bench scale in a bakery, though, might not need that level of precision and so an M1 class weight might suffice for testing.

See below for a comparison of how accuracy classes differ:

MPE = Maximum permissible error

Nominal Weight M1 MPE F1 MPE E2 MPE
1kg 50mg 5mg 1.6mg

For comprehensive guidance on accuracy classes and tolerances, you can refer to the OIML R 111-1 recommendations.

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Calibration weights are a key for performing calibrations on your weighing equipment. Read one of the posts below to learn more about scale calibration…

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