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Calibration Weights Services in Los Angeles

Calibration weights are vital when checking the accuracy and calibrating your various sets of weighing equipment. For the accurate weighing of your equipment, regular calibration of your balances is a must. When working in a laboratory, dust and water ingress might damage the sensitive parts of your weighing machines. With time, your weighing scales will be compromised. You can solve the problem by calibrating your weighing equipment at regular intervals to improve and maintain the integrity of your measurements. Calibration weights service in Los Angeles will help you maintain traceable accuracy for your weighing equipment.

Types of Calibration Weights

There are several types of calibration weights, these are

M1 OIML : These calibration weights are standard for calibrating and testing scales.

E1 OIML: These calibration weights calibrate and test micro-analytical balances.

E2 OIML: These calibration weights calibrate and test analytical balances.

F1/F2 OIML: These calibration weights calibrate and test precision electronic balances.

Classes of Calibration Weights

ASTM Class 1 Weights

These calibration weights are used with applications and balances requiring first-order accuracy. Class 1 weights are normally constructed using highly polished stainless steel. The weights are available from 10 grams to 4000 grams and 10 kilograms to 20 kilograms. Class 1 calibration weights are available in two sets ranging from 1 milligram to 100 grams and 1 gram to 100 grams.

ASTM Class 4 Weights

Class 4 calibration weights are used with less sensitive balances. They are used with applications with average accuracy and sensitivity of fewer than 0.01 grams. These weights are calibrated using satin-finished stainless steel. Class 4 calibration weights are available from 10 grams to 4000 grams and 10 kilograms to 20 kilograms. These weights range from 1 milligram to 100 grams and 1 gram to 100 grams.

Ultra Class Weights

Ultra class weights have a sophisticated design to provide superior accuracy. These weights are normally used for test applications, sensitive balances, and analytical purposes. Compared to ASTM Class 1, Ultra Class weights prove tighter tolerance between 40 and 50%. They also have either equal or exceeded the OIML Class E2 weights. Ultra class weights are constructed using highly polished stainless steel. These weights are available from 10 grams to 4000 grams and 10 kilograms to 20 kilograms. Ultra class weights have two sets ranging from 1 milligram to 100 grams and 1 gram to 100 grams.

NIST Class F Weights

These calibration weights are designed for less sensitive and higher capacity scales and balances. NIST class weights are constructed using cast iron. These weights are available from 10 kilograms to 250 kilograms and between 25 pounds and 50 pounds.

How to Choose the Right Calibration Weight

When choosing your calibration weight, there are several metrology aspects that you should follow. These are:

Scale Class

Determining the scale class is the first step in calibrating your weighing equipment. Each weighing equipment falls under one of the four scale classes. It is important to consider your weighing equipment’s tolerance and capacity when choosing the calibration weight.

Weight Class

Calibration weights are classified based on their tolerance. The three classification systems based on tolerance are NIST, OIML, and ASTM. When choosing the correct weight class, determine the weighing application and the required tolerance.


Different calibration weight classes are constructed of different materials. High-class calibration weights are constructed of highly polished metals, such as stainless steel. When handling these weights, avoid touching directly with your hands. Calibration weights for heavier scale weights are mostly constructed of cast iron. These cast iron calibration weights are painted silver in avoirdupois units and gold in metric units. Generally, the material used should be resistant to corrosion or wear and tear.


Calibration weights are available in different shapes depending on your usage. The most common calibration weight shapes are leaf, cylindrical, slotted, and grip handle. Grip handle calibration weights are mainly cast iron and are used to calibrate higher capacity scales. Slotted calibration weights are used for applications that require handling weights under test or calibration. Cylindrical calibration weights can be used in multiple applications, while leaf calibration weights are used in high precision and resolution calibration.

Test Load Configuration

When calibrating equipment, it is advisable to use as few test weights as possible to minimize uncertainties and errors. If you are testing a 50-pound balance, it is advisable to use 50-pound calibration weights instead of two 25 pound weights.

Measurement Units

Use a calibration weight with the same measurement unit as your weighing equipment. If you have weighing equipment in metric units, ensure that you purchase calibration weights. Using the same units ensures that you eliminate the chances of errors arising from the conversion of weight units.


Choosing a weight that cannot be easily magnetized is vital when purchasing your calibration weights. If your calibration weight is magnetized, you will have inaccurate and invalid measurements.

Custom Standards

When choosing a calibration weight, ensure that you purchase a custom standardized weight for a particular purpose. Each weighing equipment has its specific calibration weight according to purpose.

How to Care and Handle Your Calibration Weights

If you want to keep your calibration weights in good condition and maintain high accuracy, follow these tips:


Always keep your calibration weights in their original packaging to protect them from dust, contamination and avoid mixing the weights up. It is advisable to keep your weights in their original cases. Store your calibration weights as close as possible to your weighing equipment. It ensures that the calibration weight and your weighing equipment are at the same temperature when testing them. If you prefer storing your calibration weight at different temperatures, ensure that your equipment acclimatizes before using them.


Avoid handling your calibration weights with your bare hands. Skins cells and oils in your hands can get deposited in your calibration weight and interfere with its accuracy. It is advisable to use non-abrasive and non-magnetic tweezers when handling. If you want to clean your calibration weights, use nylon, cotton, or clean leather gloves. Avoid dragging, scraping, or scratching on the surfaces when using your calibration weights.


Before starting your testing or calibration, check for any contamination, such as dust and water. If you notice any contamination, clean your weight with a microfiber cloth or soft brush or blow the dust off. Avoid cleaning your weights with detergents or chemicals. Chemicals may react with your weight surface, forming oxides that interfere with accuracy. Always recalibrate your weights periodically to maintain their integrity, accuracy, and tolerance range.


Keeping your weighing equipment tested and calibrated is an important step in keeping your measurement work accurate and precise. At Biotechnical Services (BTS), Inc. we provide the best calibration weights services in Los Angeles, San Diego, and San Francisco. We provide a comprehensive calibration of various classes of your calibration weights using the latest technology. Our calibration laboratory is fully serviced and is ISO certified to provide premier and timely equipment calibration. Contact us today at Biotechnical Services (BTS), Inc. for the best calibration weights services.