Less scrap
Identify deviations before they affect an entire batch.
AD LAB · LK-014
Scale and weight calibration
Calibration of a scale or weight provides measurement results, errors and uncertainty. Use these to assess suitability for your process. AD LAB, metrološki laboratorij d. o. o., performs accredited calibrations within its scope.
20 mg–100 tscale range
100 mg–20 kgnominal weight values
ISO/IEC 17025accredited laboratory LK-014
SI traceabilitycomparable measurement results
What is calibration?
Comparing an instrument with a known reference
Calibration compares a scale's indication with reference standards under specified conditions. The calibration result establishes the instrument's deviation or indication error and the associated measurement uncertainty..
Calibration does not itself repair the instrument. It establishes measurement performance. Use the results to assess whether the instrument suits your process or needs adjustment, service or replacement.
Business impact
Calibration provides more than audit paperwork
Its core purpose is to help prevent incorrect decisions caused by inaccurate measurements.
Fewer complaints
Reliable measurements support evidence of conformity and consistent quality.
Lower material losses
Reduce overfilling or underdosing during dosing, filling and dispatch.
Less downtime
Planned calibration reduces the risk of unexpected equipment non-conformity.
Better processes
Comparable data supports trend monitoring and timely action.
Easier audits
Traceability and documentation help demonstrate quality-system requirements.
WHY CALIBRATE?
Find measurement errors before they become costs
A scale can display stable numbers while its indication drifts from the reference. Calibration establishes errors and uncertainty at selected points, helping you assess continued suitability and take action.
Filling and dispatch
If a filling scale systematically reads high, products may contain too little material. If it reads low, each package may receive more material than planned.
Dosing and recipes
Ingredient weighing errors can change recipe proportions, leading to repeated batches, scrap or additional quality checks.
Production acceptance checks
An incorrect measurement can accept a non-conforming product or reject a conforming one. Costs arise through complaints, returns and production disruption.
Calibration does not repair a scale or guarantee future accuracy. It records its condition at the time, supporting decisions about use, adjustment, service or replacement.
CALIBRATION INTERVALS
How often should a scale be calibrated?
Set intervals according to use and the consequences of incorrect measurement. A scale used in production control can cause rejected batches, complaints, material loss or downtime if it drifts.
Instrument use
How often do you weigh, and is the instrument exposed to wear, relocation or demanding conditions?
Cost of error
What would an incorrect decision, complaint, material loss or repeat batch inspection cost?
Results history
Previous calibrations and interim checks show stability and whether a shorter or longer interval is appropriate.
Critical checks in batch production
A business may choose monthly calibration where frequent product-acceptance decisions involve high potential error costs.
A common starting point
Many businesses begin with annual calibration and adjust the interval based on use, conditions, calibration results and interim checks.
An upper guideline
For scales, PRECIZ generally does not recommend intervals exceeding two years without a documented risk assessment, stable results and appropriate interim checks.
These intervals are practical examples and PRECIZ recommendations, not universal ISO/IEC 17025 requirements. Users must determine, document and adjust intervals for each instrument according to risk and actual results.
Service scope
Calibration of scales and weights
PRECIZ provides comprehensive support for mass measuring instruments. Accredited calibrations are performed through its subsidiary AD LAB d.o.o., accredited calibration laboratory LK-014.
| Instrument type | Scope | Examples |
|---|---|---|
| Non-automatic weighing instruments of all types | from 20 mg to 100,000 kg | micro, analytical, precision, laboratory, retail, warehouse, industrial, floor, pallet, silo and vehicle scales |
| Weights | from 100 mg to 20 kg | accuracy classes F2, M1 and M2 |
Please note: The current LK-014 accreditation annex defines the exact accredited scope, measurement capabilities and restrictions. We check your instrument when you enquire and propose the appropriate service.
AD LAB AND DOCUMENTATION
Accredited calibration is performed by AD LAB
PRECIZ provides equipment, service and support. Its subsidiary AD LAB d.o.o. performs calibration under accreditation LK-014 to SIST EN ISO/IEC 17025:2017. Accreditation applies to activities, locations and ranges in the current annex, so suitability for each scale or weight is checked when ordering.
The certificate identifies the instrument, date, location, procedure and conditions, and provides results, uncertainty and traceability. Compare results against your predefined process tolerances.
LK-014 accreditation: official annex and register
The date on the annex is its issue date. Check the official register for current accreditation status. Both links lead directly to Slovenian Accreditation.
Laboratory competence standard
What does ISO/IEC 17025 mean?
SIST EN ISO/IEC 17025 specifies requirements for the competence, impartiality and consistent operation of testing and calibration laboratories.
Accreditation means an independent body assesses personnel competence, methods, equipment, metrological traceability, uncertainty evaluation and reporting.
What does the customer receive?
- results traceable to SI units
- measured values, errors and measurement uncertainty
- clear identification of the instrument, procedure and conditions
- credible evidence for audits
- comparable results for business decisions
Who needs calibration?
Any organisation where measurement results affect quality, safety, quantity, cost, product conformity or acceptance and rejection decisions.
pharmaceuticals and biotechnologyfood industrychemical and cosmetics industriesautomotive industrymetalworking and machinery manufacturinglaboratorieshealthcare and pharmacieslogistics and warehousingretailconstructionenvironmental services and wastemanufacturing and filling operations
Regulated activities
Pharmaceutical, medical, food and other regulated environments need demonstrable, traceable measurements to support GLP, GMP, HACCP or other requirements.
Quality management systems
Organisations operating ISO 9001, ISO 14001, ISO 45001, IATF 16949 or related systems need suitable, controlled equipment.
Any process with measurement risk
Calibration is valuable where an incorrect mass causes material loss, dosing errors, batch rejection or customer disputes.
Scale calibration or legal verification?
Calibration
Calibration establishes the relationship between an indication and a reference value, providing error and uncertainty. It supports control of measurement quality, processes and risks.
Legal verification
Legal verification is a regulated procedure assessing whether an instrument meets prescribed metrological requirements. It applies to instruments used for legally regulated purposes.
Neither procedure automatically replaces the other. Some instruments need calibration, some legal verification, and some both.
How does calibration work?
Enquiry
Provide the type, model, capacity, scale interval, location and intended use.
Agree the service
Define the procedure, measurement points, location and conformity criteria.
Measurements
Trained staff take measurements using suitable traceable standards.
Certificate
Receive results, errors, measurement uncertainty and traceability information.
BEFORE AND AFTER INTERVENTION
What do as-found and as-left results show?
Specify at ordering if you need to know how the scale measured before adjustment. An initial measurement records its original condition. Following adjustment or service, a further measurement can document the final condition if agreed.
Before intervention
An as-found measurement shows the scale's error in the condition in which it was received.
Adjustment if required
Where needed and ordered, adjustment is performed and documented separately from the original result.
After intervention
An as-left measurement records the scale's condition following intervention when included in the agreed procedure.
If as-found results exceed your tolerances, assess the impact on weighings since the last satisfactory check, including affected instruments, batches or decisions. Both result sets are not automatically provided with every calibration; agree the scope beforehand.
Is the scale accurate enough for your process?
The certificate provides results; you define process requirements. At the masses you actually weigh, compare error and uncertainty with your permitted tolerance. For conformity decisions, define a decision rule and consider the consequences of false acceptance.
Define the tolerance
What deviation remains acceptable for the product, recipe or inspection?
Select relevant measurement points
Assess results in the ranges and at the masses you actually use.
Make a decision
If results fail your criteria, define corrective action and assess the impact on previous measurements.
Without an agreed decision rule, a calibration certificate is not an automatic statement of suitability for every use.
Minimum weight for small samples
For small samples, balance repeatability can contribute a large relative uncertainty. Minimum weight depends on the instrument, conditions and selected criterion. It is particularly relevant to analytical weighing and USP Chapter 41.
If you need a documented minimum weight under USP Chapter 41, it can be included in QPAC. Agree the criterion and test scope for your procedure.
Use the net sample mass
The container or tare mass does not increase sample mass or replace the required minimum net weight.
Checks between calibrations
Regular interim tests help detect changes before they affect production. Select suitable check weights and points near normal working masses, define tolerances and set a risk-based frequency.
Check
Check the indication using a control weight and, where appropriate, repeatability and eccentric loading.
Record
Record the date, instrument, weight, result and comparison with the predefined limit.
Act
If results are unacceptable, remove the instrument from use, investigate the cause and assess measurements since the last satisfactory check.
Interim checks are not equivalent to calibration, but are an important part of instrument control between calibrations.
How to read a calibration certificate
Review measurement points and conditions, not just the date on the first page.
Indication error
The difference between the scale indication and the reference value at a given load.
Measurement uncertainty
Information about the range within which a result is interpreted. Error and uncertainty are different quantities.
Statement of conformity
Included only when agreed, using defined limits and a decision rule. It does not automatically follow from calibration results.
A simple check-weight record is not a calibration certificate. For an accredited certificate, check laboratory identification, the accreditation reference and whether the service is within the current scope.
Digital instrument management
Soter: manage certificates and due dates
Soter links equipment information, inspections, maintenance and documents. Each instrument has its own digital record.
- a central measuring-equipment register
- digital equipment records with event history
- certificate and document storage
- alerts before the next calibration
- oversight across locations
- faster retrieval of audit evidence
Frequently asked questions
Scale and weight calibration FAQ
What is scale calibration?
Scale calibration establishes the relationship between the display and reference mass values. The certificate reports results, errors and uncertainty to support assessment of suitability for intended use.
What is the difference between legal verification and calibration?
Legal verification confirms compliance with prescribed metrological requirements for regulated use. Calibration establishes the relationship between an indication and a reference value, with associated uncertainty. The choice depends on intended use; both may be needed.
Does calibration replace legal verification of a scale?
No. Where regulations require legal verification for the intended use, a calibration certificate does not replace that obligation.
How often should a scale be calibrated?
The interval depends on frequency of use, required accuracy, conditions and potential error costs such as complaints or material loss. Critical production-control instruments may need monthly calibration; annual calibration is a common starting point. PRECIZ generally does not recommend intervals exceeding two years without documented risk assessment and suitable interim checks. These are examples and recommendations, not universal ISO/IEC 17025 intervals. Adjust intervals based on actual results.
Can you perform the service on site?
Yes, subject to instrument type, site conditions and service scope. Include the location, capacity, scale interval and number of instruments in your enquiry.
Does a scale need servicing before calibration?
Not always. First establish its condition and the purpose of calibration. If you need the as-found condition, take measurements before adjustment or repair. Service and adjustment are separate, documented interventions.
What does an accredited calibration certificate contain?
It connects instrument identity and calibration conditions with results, uncertainty and traceability. Actual measurement points, procedure and your tolerances matter when assessing suitability, not just the date.
Does a legally verified scale also need calibration?
It may. Legal verification confirms prescribed requirements for regulated use, while calibration provides errors and uncertainty for assessing your process. Where both are required, verification does not replace calibration.
Does calibration include adjustment?
Not automatically. Calibration establishes the instrument's condition. Adjustment and service are separate interventions to be agreed and documented. Specify as-found and as-left measurements when ordering; both sets are not automatically included in every calibration.
What if as-found results exceed the tolerance?
Remove the scale from use temporarily, define corrective action and assess which measurements, batches or decisions since the last satisfactory check may be affected. After intervention, check and document its condition before returning it to service.
When should a scale be checked between calibrations?
Set interim-check frequency according to use, conditions and consequences of error. Use control weights at relevant working points, record results and compare them with predefined limits. If results are unacceptable, remove the instrument from use and assess previous weighings.
What is the difference between accredited and non-accredited calibration?
Accredited calibration is performed within the valid scope of a laboratory whose competence is independently assessed by an accreditation body. Non-accredited calibration may provide useful results but does not carry that body's confirmation for the particular procedure. In both cases, check results, uncertainty, traceability and fitness for purpose.
Why choose accredited calibration?
Choose it when your requirements, customers or audits call for independently assessed laboratory competence for the procedure and range. Results and uncertainty help determine instrument suitability. Accreditation applies only to services within the laboratory's valid scope.
How can I identify a non-accredited calibration certificate?
Check for a clear accreditation reference or appropriate mark covering the calibration and confirm the procedure is within the laboratory's current scope. Do not treat a certificate as accredited if it is labelled non-accredited or has no accreditation reference. A laboratory logo or mention of ISO/IEC 17025 alone is insufficient; ask the issuer if unclear.
How do I check whether a company's accreditation is valid?
Find the company and accreditation number in the official Slovenian Accreditation register; for AD LAB calibration, use LK-014. Check current status and the valid annex for procedures, ranges, locations and restrictions. Accreditation does not cover every service automatically.
Request a calibration quotation
Send an instrument list or nameplate photographs. We will check the scope and propose a service and quotation for your process and location.
PRECIZ d.o.o. · Cesta XIV. divizije 5, 2000 Maribor