What is temperature calibration?

Temperature calibration refers to the calibration of any device used in a system that measures temperature. Most importantly, this usually means the temperature sensor, itself, which is typically a platinum resistance thermometer (PRT or PT-100), thermistor, or thermocouple. Readings from these thermometers are made by “thermometer readout” devices which measure their electrical outputs and convert them to temperature according to the International Temperature Scale of 1990 (ITS-90).

Thermometers are typically calibrated by placing them in a stable temperature environment (heat source) and comparing their output to that of a calibrated “reference thermometer” or “standard thermometer.” Fluke Calibration provides three general categories of heat sources:  industrial heat sources (dry-well calibrators, Micro-Baths, etc.) for field use; fluid baths and thermocouple furnaces for laboratory use; and fixed-point cells for “primary” calibrations.  Fluke Calibration also offers a variety of reference thermometers, including SPRTs, and thermometer readout instruments.

In addition, Fluke Calibration provides a variety of laboratory and field solutions for calibrating the electronics used in temperature measurement circuits.

International Temperature
Scale of 1990 »

Field, laboratory, and primary temperature calibration

Field temperature calibration (or “industrial” or “portable” temperature calibration) applies to thermometers being tested outside of a laboratory environment, typically to accuracies ranging from 5 °C to 0.5 °C. Dry-wells, Metrology Wells, Micro-Baths, IR targets, and other portable heat sources provide stable temperatures, while portable thermometer readouts and thermometer standards can provide reference temperatures beyond that available directly from the heat source.
Field temperature calibrators »
Laboratory or secondary temperature calibration relates to the calibration of reference-grade PRT or PT-100, precision thermistors, and noble-metal thermocouples. Ultra-stable and uniform temperature baths and horizontal furnaces (for the high temperatures needed by thermocouples) are used along with SPRT reference thermometers and high-accuracy thermometer readouts.  Such systems can provide calibration accuracies from 0.5 °C to 0.02 °C.
Thermometer Readouts »
Fixed-point or primary temperature calibration utilizes fixed-point cells, such as the Triple Point of Water, which provide extremely accurate and repeatable temperature when they are properly “realized,” typically in a laboratory setting. Such systems are used for calibrating SPRTs and noble-metal thermocouples and can be as accurate as 0.001 °C. 
Fixed-point cells »

Hart Scientific products and the Fluke Calibration brand

In 2001, Fluke acquired Hart Scientific, located in American Fork, Utah. Temperature products continued to be sold under the Hart Scientific label until 2010 when Fluke introduced the Fluke Calibration brand, which includes the Hart Scientific products as well as electrical, RF, pressure, and flow calibration products. Today, some temperature products are manufactured at Fluke headquarters in Everett, Washington, while fixed-point and thermometry products continue to be manufactured in Utah.  We continue to rely on the exceptional team of experts that previously made Hart Scientific the world’s leading brand for temperature calibration.  

Related reference materials

Understanding Temperature Calibration Uncertainties »
Automating Temperature Calibrations »
Fluke Calibration’s Scope of Accreditation for Temperature Calibrations »
Establishment of a Primary Standards Laboratory »
Establishment of a Secondary Laboratory »
Infrared Temperature Calibration 101 »

Calibrating a temperature sensor can be a challenge, but is very doable with some know-how and the right products. The first step is to understand the thermometer being calibrated:  What type of electrical signal does it output or is it entirely mechanical? What are its physical characteristics (size, shape, size and shape of sensor hidden inside the probe sheath, etc.)? Over what temperature range is it used? And what accuracies are relied on over those temperatures? Can it be calibrated in a laboratory or must it be calibrated in the field or even in-situ?

The answers to these questions help define the products and processes that comprise the right solution for you. One quick and easy way to work through these answers and define a calibration solution that is fully reliable but not overdone is to contact our application experts at 1.877.883.8225.  They have a great deal of knowledge and experience adapting calibration solutions to a wide variety of requirements.

If you have a general idea of what you’re looking for, but want to find just the right product(s) to meet your need, these selection guides provide a quick way to compare our various product offerings and provide links to take you directly to complete information about each product.

Related reference materials

Product Selection Guides

Primary standards

Thermometer readouts

Thermometer probes

Constant temperature calibration baths

Industrial temperature calibrators

Temperature calibration: Tips and tricks from the real world  
Nobody offers a more complete line of temperature calibration equipment than Fluke Calibration. From ITS-90 fixed-point cells to handheld temperature sources—combined with easy to use and extremely precise thermometry systems—we can help provide the temperature calibration equipment you need to resolve your challenges in the lab or on the shop floor. Use the Quick Links at right or the descriptions below to explore our vast array of solutions.
Quick Links


  • ITS-90 Temperature Standards »

    The defining instruments of the ITS-90 (International Temperature Scale of 1990) are Standard Platinum Resistance Thermometers (SPRTs) and ITS-90 fixed-point cells. SPRTs are calibrated in fixed-point cells to provide the highest possible temperature accuracy. Primary standards offered by Fluke Calibration include: long-stem SPRTs; capsule SPRTs; triple point of water cells; metal fixed-point cells; maintenance baths and maintenance furnaces for fixed-point cells; standard resistors.
    ITS-90 Temperature Standards
  • Calibration Baths »

    Fluke Calibration temperature baths provide optimal temperature environments for “secondary” or “comparison” temperature calibrations. They offer unsurpassed stability and uniformity, a large working volume, and flexibility for performing thermometer calibration on calibrating a variety of temperature sensors. A world-class temperature controller and 30+ years of experience make these the choice of National Metrology Institutes and calibration laboratories worldwide. Fluke Calibration temperature baths include: compact temperature baths; deep-well temperature baths; standard calibration baths; resistor maintenance baths; ice-point baths; bath / temperature controllers.
    Calibration Baths
  • Industrial Calibrators »

    A temperature calibrator, often called a thermometer calibrator, is used to correct inaccuracies in installed thermometers and temperature sensors, because temperature measurement is a critical parameter in many industrial processes. Although simulators are sometimes called temperature calibrators or thermometer calibrators and may be used to provide thermometer calibration for the electronics in an installed system, a temperature source with a calibrated reference sensor is still required to provide a complete and meaningful calibration. Fluke Calibration industrial and field temperature calibrators include: Metrology Wells; Field Metrology Wells; field dry-well calibrators; handheld dry block calibrators; Micro-Baths; large target infrared calibrators; field IR calibrators; ice-point dry-well; and thermocouple furnaces.
    Industrial Calibrators
  • Probes/Sensors »

    Fluke Calibration provides high-quality secondary platinum resistance thermometers (PRTs); industrial PRTs; high-temperature, fast-response, and other special-application PRTs; thermistor standards; secondary thermistor probes; type R and type S thermocouples. These probes may be used for temperature measuring, temperature calibration, temperature monitoring and temperature validation.
  • Digital Thermometer Readouts »

    Fluke Calibration precision digital thermometer readouts are designed specifically to measure temperature sensors for calibration. Because Fluke Calibration thermometer readouts are designed for thermometer calibration, they offer many advantages, especially accuracy and convenience. Fluke thermometer readouts include: Super-Thermometers; Black Stacks; Chub-E4; Tweeners; handheld readouts; and the DewK thermal-hygrometer for environmental monitoring.
    Digital Thermometer Readouts
  • Multifunction Calibrators »

    These bench multifunction calibrators source, simulate, and measure pressure, temperature, and electrical signals with exceptional precision. They can automate calibration procedures and maintain a wide range of temperature and pressure transmitters, multi-meters, pressure gauges, and more.
    Multifunction Calibrators
(If you are considering a purchase for use outside the United States, please use the country selector at the top of this page to select the country of final destination for the product, which will take you to the appropriate information for your country.)
Fluke Calibration's temperature calibration products are sold in the United States through our factory-direct temperature applications specialists located in American Fork, Utah, as well as by a team of direct sales people located around the country who sell all Fluke Calibration products.

To request a quote, please click here (quotes are usually sent within 24 hours): 

To speak with a factory-direct expert or regional sales manager, please call +61 2 8850 3333.

You can also email us at auinfo@flukecal.com.

Fluke Calibration is committed to outstanding product quality, world-class metrology, and excellent post purchase service and support. In spite of our commitment to continuous improvement, things sometimes go wrong – but when they do, we want to be there for you with an excellent response. In addition, when you need routine service work, such as an instrument recalibration, we want you to have an experience that will leave you eager to return.

For specific information about service and support in your area of the world, select your country from the selector at the top of this page, then click on the Service and Support menu.