Weighing is one of the most common tasks in the laboratory. Balances have now been perfected to such a degree that no special weighing rooms are needed. Explore how to weigh in the right way. Technological advances in electronics have considerably simplified the operation of balances, reducing weighing times. Moreover the touchscreen digital display makes operation of the balance intuitive.

1. What is an analytical balance?
An analytical or semi analytical balance is a form of scale that measures mass to a high degree of precision.
It has a weighing capacity in the range of 100-500 g (typically 200 g) and a readability of 0.1 mg – 0.001 mg. Analytical balance sensitivity requires it to be protected by a draft shield or an enclosure.
METTLER TOLEDO XPE, XSE and XS analytical balances are equipped with the SmartGrid weighing pan minimising air turbulence and therefore shorten stabilization times and allowing faster weighing results.
2. Where are analytical balances used? What are the application areas of analytical balances?
An analytical balance scale, often called a "lab balance", permits quantitative analysis of a sample. Typical applications of an electronic analytical balance include: Sample/standard preparation, formulation, differential weighing, density determination, interval weighing and pipette routine testing.
3. How to weigh on an analytical balance?
To start a weighing operation, open the door and place a container on the pan using gloves or tweezers.Close the door and wait until the value stabilises, noting the weight. Clear the display by pressing the tare button until it reads 0.0000 g. Add the sample until the desired weight is reached. Close the door and again wait for stability - record the net weight. If the instrument is unplugged for cleaning, allow readjustment time before reuse.
METTLER TOLEDO’s analytical balances are designed for easy cleaning with draft shield disassembly in seconds, and dishwasher-safe panels. Cleaning Recommendations and Regulations for Balances
4. What are the effects of static electricity on an analytical balance and how to eliminate static charges?
Electrostatic charges can cause unstable, non-repeatable weighing results. Static electricity exerts a force on the weighing pan, which directly affects analytical balance results. Precautions to reduce these effects include:
- Ensure adequate air humidity (≥ 45%...50%)
- If possible, use antistatic weighing containers (metal is ideal)
- Avoid rubbing containers
- If the sample is small enough, use a metal dish with an edge to help shield the electric fields
To ensure analytical balance static elimination, discharge the sample and container with an ionizer before weighing.
Read additional information on electrostatic charges and the physics behind it.
5. What is analytical balance uncertainty?
When making measurements there is always an element of uncertainty. An estimate of doubt that surrounds it (the uncertainty) is key to any measurement. This is determined by measuring the performance of the balance, properties of the weighing object and environmental surroundings. Determination of measurement uncertainty is an integral part of a balance calibration.
6. Why should I calibrate my analytical balance?
Analytical balance calibration ensures that weighing equipment is accurate and satisfies standards such as ISO, GLP/GMP, IFS, and BRC. Documented calibration procedures indicate the quality of measurements, and should be performed regularly throughout the balance’s lifetime.
Calibration should not be confused with adjustment of a balance, and must be repeated after adjustment/repairs. Read more on Calibration.
6. How should I calibrate my analytical balance?
The calibration of an analytical balance is performed by an authorized service technician following a standard procedure, using calibration software:
- Establish how well the instrument performs by testing the relationship between measurement standards and indications through calibration.
- Verify whether the instrument meets specific requirements with a Pass/Fail statement.
- If requirements are not met, adjust the instrument so that any deviation does not exceed tolerance limits.
- Re-calibrate the instrument to confirm compliance with specified tolerances.
In between calibration intervals, routine testing by the user can detect potential issues.
METTLER TOLEDO has developed a global scientific standard for the secure selection, calibration and operation of weighing equipment, GWP®, or Good Weighing Practice™.
7. Which tolerances apply to balance calibration?
Tolerances determine whether a balance or scale behaves "well enough" to meet a particular set of process requirements. Tolerances set the criteria to issue a Pass/Fail statement. Tolerances come from a variety of sources, including:
- Legal tolerances:
Legal tolerances stipulated by OIML R76 or NIST Handbook 44 (US only) assess legal for trade requirements. These tolerances are quite large and easily met with laboratory balances, or when weighing at the lower end of the measurement range. - Manufacturer tolerances:
Manufacturer tolerances ensure that equipment meets manufacturer specifications. Manufacturer tolerances do not consider user specific process requirements, and are unsuitable for improving the weighing process. - Process tolerances:
Specific process tolerances defined by the user, support process improvements and savings on material, waste and rework. For scales in a legal for trade application, process tolerances should therefore be applied in addition to legal tolerances.
Legal tolerances protect consumers but do not consider specific producer requirements. Optimising process tolerances that are applied to measuring instruments can have a large impact on process profitability.
8. What is the analytical balance minimum weight?
Every analytical balance minimum weight is different, depending on the performance of the load cell, its location, and ambient conditions. The minimum weight is the accuracy limit of the instrument, below this minimum weight, the relative measurement uncertainty (absolute measurement uncertainty divided by the load, usually indicated in %) is larger than the required weighing accuracy, and the weighing result cannot be trusted.
In order to determine the minimum weight for a balance, measurement uncertainty needs to be assessed in the working environment. Alternatively repeatability, as the dominant source of error in the lower balance range, can be assessed to determine the minimum weight, carried out using a small weight, below 5% of balance capacity.
The MinWeigh function of METTLER TOLEDO analytical balances, installed by a certified technician, monitors the minimum sample weight of the balance. If a weighing is below the determined acceptable minimum value, the balance display turns red.
9. Analytical balance accuracy and precision – what is the difference and how to test them?
Precision refers to the closeness of two or more measurements to each other. Accuracy refers to the closeness of a measured value to a known value, and is based on readability, repeatability, non-linearity and eccentricity. Accuracy can be tested using
- An external reference weight with a known mass (traceable calibrated weight)
- Automatic internal adjustment using a reference mass built into the balance
- Accuracy can only be determined by testing of the instrument at its location of use.
View Laboratory Balances Tutorial - Basics and Weighing Influences course on good weighing practice.
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Excellence Level Balances | Advanced Level Balances | Standard Level Balances |
Outstanding weighing performance and innovative sample-handling technologies help make your challenging weighing tasks efficient, error-free and compliant. | When you need great performance and durability, Advanced Level Balances are the right choice. Intuitive operation and integrated applications make your weighing process fast and convenient. | Enter the professional world of weighing with our robust and easy-to-use Standard Level Balances. High-quality construction and solid performance ensure consistent and precise weighing results. |
Outstanding weighing performance and innovative sample-handling technologies help make your challenging weighing tasks efficient, error-free and compliant.
When you need great performance and durability, Advanced Level Balances are the right choice. Intuitive operation and integrated applications make your weighing process fast and convenient.
Enter the professional world of weighing with our robust and easy-to-use Standard Level Balances. High-quality construction and solid performance ensure consistent and precise weighing results.
Services

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We support and service your measurement equipment through its entire life-cycle, from installation to preventive maintenance and calibration to equipment repair.
Calibration & Quality

Publications

Guide: Weighing the Right Way

Brochure: Excellence Line Analytical Balances
Worry-free Weighing Follow the Green Light
METTLER TOLEDO introduces a new dimension in analytical weighing with a combination of intelligent features to make your daily weighing tasks easy and error-free. You not only benefit from the outstanding weighing performance of Excellence analytical balances but you can also be sure of full regulatory compliance and high process security.
- Easy Balance Management
- Electrostatic Solutions
- Full Process Control

White Paper: The Green Light
METTLER TOLEDO’s new Excellence Plus range of analytical balances incorporates a green status light to confirm that all the factors required for precise and accurate weighing in a Good Manufacturing Practice (GMP) regulated laboratory are correct and that the balance is ready for use. If one of these factors is not ready, then the light turns yellow to warn but indicate that it is still safe to weigh, or red to tell an analyst not to proceed. When the problem is corrected, the analyst gets the green light for weighing.
Read the White paper to learn more.

Catalog: Accessories for XPE/XS Balances
Every weighing application and every workplace is unique. Whether your focus is on accurate sample preparation, error-free data handling or more ergonomic processes, you can combine XPE and XS accessories to create a dedicated weighing solution which meets your precise requirements. Explore our comprehensive range of accessories for more ideas on how you could benefit.

Webinar: Employing a Lean Lab Approach to Optimize Lab Processes
Work smarter not harder
Practical advice on getting started with lean lab. Lean tools and methods for use in established labs or new lab design.
Watch the webinar to learn more.
LabX Software

LabX® Software
LabX® Software brings power to your laboratory bench with automatic data handling, high process security and full SOP user guidance.
- One software for many instruments
- Full step-by-step user guidance
- Integrate LabX system to other lab systems

LabX for Balance
LabX software brings the power and flexibility of SOP workflow control onto the balance touchscreen. Technicians can work entirely from the balance terminal without the need of a PC on the lab bench. All data is automatically stored on a secure centralized database.

LabX for Quantos
LabX software for Quantos allows you to automate your processes with full traceability and data security. Powerful workflow building tools creates the process to match your own SOP.