How to Properly Store and Handle Test Weights

Test weights are used to perform calibrations. It is very important to maintain their accuracy, and to do so there needs to be proper handling and storage of the test weights. If their accuracy is compromised, then calibrations will be off and product will be out of spec.


Class 1-7 test weights are held to the American Society for Testing and Materials (ASTM) standards and are most used in the laboratory.

These test weights should be kept in their original packaging. This with help keep dust and residue off the weights and keep them together. Store the weights near the balance to ensure they are controlled within the same temperature during use. An ideal temperature is 68 degrees Fahrenheit ± 2

When handling the test weights, be sure to use non-magnetic and non-abrasive tweezers. When possible, wear approved gloves. You should never use your bare hands to handle the test weights. The oils from your skin can affect the accuracy.


Class F test weights are held to NIST standards and are most often used in an industrial setting to calibrate larger scales.

These test weights aren’t required to be in as specific conditions as Class 1-7 test weights due to the tolerances involved. Just store these test weights in a clean dry environment and away from major contaminants.


Keeping your test weights under these conditions will save money because failure to do so results in re-calibration and decontamination of the test weights.

If you are in need of a calibration, we would be happy to assist you.




Calibration Weights

[Video] How To Verify a Scale Using Certified Test Weights

Our Senior Service Technicians, Shayn, demonstrates how to verify a scale using certified test weights! Along the way, he explains what verification is, why it’s important and the best practice for your own verification process.



For inquires or to purchase certified test weights, quickly and easily request a quote today!

Scale Verification with Test Weights

For most industries, scale accuracy is a critical part of operations and can directly impact the bottom line. Grand Rapids Metrology certifies weighing equipment to the highest standards in the metrology industry. However, there are numerous factors that can affect the accuracy of your scale between GRM planned maintenance visits; such as debris building under platforms, scales being bumped and becoming out of level, tare weights being entered and not cleared, etc.

Quality Auditors are increasingly asking companies how they ensure their scales are operating correctly after scheduled calibration. To solve this problem, GRM recommends that scales are periodically verified using certified test weights that safeguard accuracy and functionality.

Routine tests can be performed at various points of use and for various test weight ranges and intervals. For each test situation, the scale is zeroed then tested with known certified weights. Results can be evaluated graphically or statistically. Grand Rapids Metrology recommends that the scale be tested in the same range in which the scale is used. For example, if a scale is used to weigh 50 lb. boxes, then we recommend using at least (1) 25 lb. and (1) 50 lb. weight and testing your scale at 25 lb., 50 lb. and 75 lb. This will ensure that the scale is not only accurate at the target weight, 50 lb., but also linear through the weighing range.

GRM offers a wide array of certified test weights for purchase. Our primary manufacturers of mass and test weights include Rice Lake Weighing Systems, Sartorius, and Troemner. Please note this verification procedure does not replace the service, calibration, and planned maintenance performed by Grand Rapids Metrology. This process should be used to verify scale accuracy and reinforce quality importance. For more information of the benefits and sale of calibration and test weights, contact a GRM Sales Representative or call us at 800.348.5701!