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Balance and Scale Calibration - Service

With the Accuracy Calibration Certificate (ACC)

Home Laboratory Weighing Balance and Scale Calibration - Service

Like all measurement devices, balances and scales have inherent uncertainty. To achieve accurate and consistent weighing results, the performance of a balance or scale must be defined. The calibration of your weighing device determines that measurement uncertainty in its actual place of use. This plus/minus range on your results lets you know with precision how accurate your results are.

With our Accuracy Calibration Certificate (ACC), you can check if what you see is actually what you get.

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Determine the Accuracy of Your Balance or Scale
Determine the Accuracy of Your Balance or Scale

The Core Certificate:
Determine the Accuracy of Your Balance or Scale

The Accuracy Calibration Certificate (ACC) determines the performance (measurement uncertainty) of a device over its entire weighing range. With our ACC calibration service, you benefit from:

  • A globally harmonized method  
  • A calibration procedure set up according to the globally acclaimed EURAMET cg-18 calibration guidelines
  • Results in an easy-to-understand report
  • Various annexes to analyze the calibration results, each giving a clear pass/fail statement for certain tolerances applied

Locally Accredited Calibration

In 30+ countries we offer locally accredited versions of the calibration certificates according to ISO/IEC 17025. These versions are based on the ACC–and therefore offer the same benefits–but come with the approval and logo of the local accreditation body. Therefore, you gain the assurance of the global ACC in locally accepted terms.

For instance, the A2LA version is available in the US, the DAkkS-ACC in Germany, and the CNAS version in China.

See all locally accredited certificates

Ask your local METTLER TOLEDO representative to find out more. 

Find your local contact

Locally Accredited Calibration
Locally Accredited Calibration

GWP Certificate Annex: Make the Fit-for-Purpose Check

The GWP™ Certificate as an annex to the ACC sets a new benchmark in terms of weighing accuracy. How? By:

  • Linking the performance of your balance or scale to your specific processes
  • Giving you certainty that your device meets your individual requirements
  • Including as-found and as-left test results
  • Showing your Safe Weighing Range with a visual representation

This gives you peace of mind that the device is fit-for-purpose in terms of accuracy and supplies you with the proper documentation to prove it.

Look at a GWP Certificate sample

Learn more about GWP™ (Good Weighing Practice™)

GWP® Certificate Annex: Make the Fit-for-Purpose Check
GWP® Certificate Annex: Make the Fit-for-Purpose Check
Legal Metrology Annexes: Check Against Maximum Permissible Errors
Legal Metrology Annexes: Check Against Maximum Permissible Errors

Legal Metrology Annexes: Check Against Maximum Permissible Errors

Legal metrology annexes provide clear statements on whether legal metrology regulations and Maximum Permissible Error (MPE) guidelines are met. National law regulates which applications are subject to these legal controls, the two most important of which are the international OIML recommendation R76-1 and the US NIST Handbook 44.

Custom Annex: Check Your Balance or Scale Against Legacy Tolerances

The Custom Annex to your balance or scale calibration provides pass/fail statements for customers that need to satisfy legacy quality assurance requirements with individually defined repeatability, eccentricity, and error of indication tolerances. 

Custom Annex: Check Your Balance or Scale Against Customer Tolerances
Custom Annex: Check Your Balance or Scale Against Customer Tolerances
As-Found and As-Left Calibration

As-Found and As-Left Calibration

As-found calibration data tells you how accurately the device performed prior to the adjustment made by the service technician, while as-left calibration data tells you how the device performs after any corrective actions. As-left also defines the accuracy you can expect from your weighing results going forward.

Various regulations make it mandatory for calibrations to document as-found and as-left calibration data (such as certain Pharmacopoeias and ISO/IEC 17025).

1. How often do I need to calibrate my balance and scale?

The frequency of calibration depends on how the device is used, the process tolerances applied, and the criticality of the weighing results. Our GWP Verification service gives you concrete guidance for a customized calibration plan that meets the requirements of your process and weighing devices. 

Learn more

2. What is the measurement uncertainty of a balance or scale?

Like all the measurement devices, balances and scales have an inherent measurement uncertainty. This is where calibration comes in. It quantifies how accurate your weighing results really are by determining the measurement uncertainty. This gives you a plus/minus range for each of your weighing results.

Find out more in our video about calibration
Learn more with the white paper "Calibration of Weighing Instruments"


3. What is the safe weighing range? How does it help with accurate weighing?

The safe weighing range
The safe weighing range

The safe weighing range is the range in which the balance or scale gives the most accurate results. This range lies between a scientifically determined lower accuracy limit (minimum weight determined through calibration) to which a safety margin is added (defined by the selected safety factor) and the maximum limit (capacity) of a balance or scale.

Process quality requirements are met if the smallest net weight lies within the safe weighing range.

Since most manufacturers do not declare the lower limits for their devices, it's important to define your tolerances to ensure accurate results. 

4. How can I ensure accuracy between calibrations?

Over time, the performance of your balance or scale can change due to environmental influences, wear and tear, and non-obvious damage. With routine testing performed by the user, you can check if the weighing device performs accurately enough to meet your needs until the next calibration.

Find out more about routine testing

5. Are the different calibrations available for different types of balances and scales? For instance, does METTLER TOLEDO offer an analytical balance calibration, a precision balance calibration, and an industrial scale calibration?

Our Accuracy Calibration Certificate (ACC) works on all balances and scales, whether they are analytical balances, precision balances, or production or truck scales. Therefore, you get one calibration solution that is applicable for all your weighing devices.

6. What is the difference between a calibration and a test report?

Calibration: Calibration defines the performance of a weighing device by determining the measurement uncertainty of the device in its actual place of use through three individual tests: repeatability, eccentricity, and error of indication.
Knowing the measurement uncertainty over the whole weighing range will give the expected uncertainty of any measurement displayed on a balance or scale.

Test report: Similarly, a test report is a performance check of a balance or scale that uses one or more individual test points. However, the test report only displays the results of these weighing tests as well as any potential errors they may indicate. It does not define the measurement uncertainty of a balance or scale and therefore does not define the full performance of the device. Test reports are typically not enough to prove compliance with internal or external quality standards.