Importance of Refractometer Calibration


Refractometer calibration is one of the most important yet least understood concepts related to the use of refractometers. Substantially all measuring systems are prone to change over time; refractometers are no exception. It is therefore necessary to identify when this change has occurred and to counteract its effects through the process of calibration to insure the highest possible measurement accuracy.

The periodic calibration of refractometers is necessary to ensure their continued accuracy and traceability. The calibration process ensures that measurements made on a specific instrument will comply with predetermined specifications and will be repeatable anywhere in the world. Calibration is the act of establishing, under specified conditions, the relationship between values read on a refractometer and the corresponding values represented by a reference standard, and the subsequent adjustment of the refractometer to match those values.

In the case of a refractometer, the reference standard is generally a fluid that has been prepared or standardized on instrumentation that is traceable to a nationally or internationally recognized source; alternatively, it may be a fluid such as distilled water that has accepted physical properties. Traceability relates individual refractometer results through an unbroken chain of calibrations back to a national standard, a fundamental physical property, international standards, or a consensus standard. At MISCO, we provide traceability back to the U.S. National Institute of Standards and Technology (“NIST”). 

Calibration Intervals - How often should I calibrate?

How often a refractometer needs to be confirmed/calibrated depends on how quickly it drifts out of tolerance. This depends primarily on the conditions in which it is used. Calibration/verification intervals should be established for refractometers based on your experience and on a statistical analysis of confirmation results, proficiency tests, and gauge R&R studies. Additional considerations should be given to the importance of their accuracy to your operation, how frequently they are used, and how roughly they are handled.

Instruments used in environments where there are extreme temperatures, wide temperature fluctuations, humidity or pressure variations, high condensation, dirt, dust and other debris will require more frequent intervals of field confirmation/calibration.

In the absence of empirical data, it is generally agreed that a traditional refractometer should be frequently field calibrated at least at one point on the scale. Additional calibration/confirmation checks may be necessary if the instrument is dropped, subjected to rough handling, or is subjected to conditions of extreme temperature cycling. Digital instruments should be calibrated to water daily.

It is further recommended that a certified traceable calibration be done at minimum on a yearly basis. Having a traceable calibration performed once a year decreases measurement uncertainty and establishes a baseline upon which field confirmation/calibrations are subsequently made. It also ensures that every instrument will be checked by a specially trained technician at least once a year. An annual traceable calibration is NEVER a substitute for frequent field confirmation/calibrations. 

Additional Resources:

RMA Form

The Difference Between Level I & Level II NIST Calibrations

Order a NIST Calibration

MISCO Refractometer Calibration

NIST Traceable
All MISCO certified calibrations are traceable to the National Institute for Standards and Technology (NIST).

Calibration Lab
We are proud of our state-of-the-art calibration lab. It has a high-efficiency air handler system which maintains a precise 20 degree Celsius reference temperature. We only use the highest quality equipment available to ensure that uncertainty of measurements is kept to an absolute minimum.

Trained / Experienced Personnel
Our calibration personnel are all completely trained and experienced on the use of all calibration equipment and follow strict written procedures which are compliant with ISO/IEC 17025.

Dedicated to Quality
For more than sixty years MISCO has been dedicated to the highest professional standards of quality.

FAST Service
Units sent in for calibration are usually returned in one week or less.

Quality You Can Measure™
The overall accuracy of a refractometer is dependent upon the quality and calibration of the instrument. Uncertainty in measurement results can be kept to a minimum by controlling calibration related factors such as environment, reference material, comparison instrumentation, and training of personnel.

Build Your Own Refractometer

While we pride ourselves in having one of the largest selections of refractometers available, we recognize that every user is different and that there may not be a one-size-fits-all solution to your measurement needs. Build-Your-Own Refractometer allows you to design a custom refractometer to your exact specifications. Just select the desired number of scales, choose protection options, and then add accessories to your design - truly making it your own. When you're done you can choose to print a custom quote or place the order immediately! Give it a try! Of course, call us anytime for personalized service. 866-831-1999

Build Your Own Refractometer

Our Build-Your-Own Refractometer section allows you to design a custom refractometer to your exact specifications. First, select the measurement scales. Next, add options and then accessories to your design. Finally, you can print a custom quote or order immediately. TRY IT NOW!


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Contact MISCO

6275 Cochran Road, Solon OH 44139

Toll Free 866-831-1999

Phone 440-349-1500 

Fax 440-349-1511