Can Home Thermometers Be Calibrated?

Thermometers are used to measure the temperatures of air, food and people. A correct temperature reading is important for many reasons, including the prevention of health risks. Calibrating your thermometer will ensure that it is accurate and precise.

Importance

• A thermometer should be calibrated the first time it is used, regardless of the type of thermometer it is or what it will be used for. There are many factors that can affect the accuracy of thermometers. For example, if they are dropped on a floor, used to measure very hot or cold temperatures, or just used often, they should be recalibrated to ensure accuracy in temperature measurement.

Boiling Water Calibration

• A thermometer can be calibrated by sticking its sensor into a pot of boiling water for 30 seconds. The boiling point of water is 212 degrees Fahrenheit at 1,000 feet, so that is what the thermometer should read. If it does, you know the thermometer is accurate.

Cold Water Calibration

• You can also calibrate a thermometer by inserting it into an insulated glass full of crushed ice and water. Let the water sit for about five minutes so the temperature comes through the ice. Hold the thermometer in the center of the glass for 30 seconds and it should read 32 degrees Fahrenheit. This is the most reliable method of calibrating a thermometer.

Digital Thermometer Calibration

• If you have a digital thermometer, use the ice method to calibrate it because high temperatures may cause it to crash. Most digital thermometers can be inserted into the water but don't let their tips hit the bowl. Press the "Cal" or "Calibrate" button until the display indicates the temperature has reached 32 degrees Fahrenheit.