Is My Kinsa Thermometer Inaccurate?
At Kinsa, our goal is to make sure your thermometer gives accurate and consistent results. Still, even when used correctly, different kinds of thermometers—and even different Kinsa models—can show slightly different numbers. Here’s why that happens and how to get the best results.
Understanding Body Temperature
Normal body temperature is different for each person and can also change with age, time of day, and where you take the reading. The best way to know your normal temperature is to measure it when you feel healthy.
- Take your temperature twice a day (morning and late afternoon).
- Record both in the Kinsa app.
- Average those two numbers to find your normal temperature. If your current reading is about 1°F higher than your normal, you may have a fever.
Different Thermometers Measure Different Parts of the Body
Not all thermometers check temperature in the same way:
- Rectal thermometers measure the body’s core temperature, which is usually the most accurate.
- Oral thermometers go under the tongue and can be affected by eating, drinking, or breathing through the mouth.
- Ear thermometers check the temperature inside the ear. They can be accurate but only if placed correctly.
- Forehead thermometers measure the surface of the skin, which is naturally cooler than the inside of the body.
Even if all are used perfectly, a rectal reading can be 0.5°F to 1°F (0.3°C to 0.6°C) higher than an oral reading. A forehead reading is usually a little lower than both.
Different Brands Can Show Slightly Different Numbers
Each thermometer brand works a bit differently.
- Some round up or down in unique ways.
- Others adjust for room or skin temperature.
- The shape or depth of the thermometer tip can also make a small difference.
Because of these factors, it’s normal for different brands—or even two devices of the same kind—to show slightly different readings. What matters most is that your thermometer gives steady and repeatable results, not that it matches another brand exactly.
Small Differences Don’t Mean It’s Wrong
If your Kinsa thermometer shows a number that’s a little higher or lower than another brand, that doesn’t mean it’s inaccurate. Each thermometer is designed and tested to meet medical accuracy standards for how it measures temperature. For example, your ear thermometer isn’t wrong for being different from your forehead thermometer—they’re just checking different things.
How to Get the Most Accurate Reading
To get the best results:
- Always use the same type of thermometer when comparing temperatures.
- Follow the instructions carefully—placement and timing are important.
- If you need to, take more than one reading and look for patterns instead of focusing on one number.
- Make sure your thermometer is clean and at room temperature before using it.
When to Be Concerned
If a temperature seems too high or low and doesn’t match how someone feels, take another reading with the same thermometer. If it still seems off, call your healthcare provider for advice.