Is ear or forehead thermometer more accurate? - The Environmental Literacy Council (2025)

The quest for accurate temperature readings is a common one, whether you’re monitoring a sick child or keeping tabs on your own health. With various thermometer options available, the choice between ear and forehead thermometers can be confusing. So, which is more accurate? The short answer, based on current evidence, is that forehead thermometers, when used correctly, are generally considered more accurate than ear thermometers. While both have their advantages and drawbacks, understanding these nuances is key to obtaining reliable temperature readings.

Accuracy Showdown: Forehead vs. Ear Thermometers

Forehead (Temporal) Thermometers

Forehead thermometers, also known as temporal artery thermometers, measure temperature by scanning the temporal artery on the forehead. They use infrared technology to detect the heat emitted from this artery. Several factors contribute to their accuracy:

• Direct Arterial Measurement: Forehead thermometers directly target the temporal artery, which is a major artery close to the skin’s surface. This proximity provides a more reliable reflection of core body temperature.
• Ease of Use: They are generally user-friendly and non-invasive, making them suitable for all ages, including infants and young children. A quick scan across the forehead is usually all it takes.
• Comparable to Probe Thermometers: Studies suggest that their accuracy is often comparable to that of traditional probe thermometers, when used correctly.
• Fewer Invasive Concerns: Forehead thermometers do not require physical insertion into the body, reducing the risk of cross-contamination.

However, the accuracy of forehead thermometers can be affected by several factors:

• Environmental Factors: Direct sunlight, cold temperatures, or a sweaty forehead can significantly skew temperature readings.
• Technique Variations: Improper technique, such as holding the scanner too far away from the forehead, can lead to inaccurate results.
• Hair and Head Coverings: Any head covering, hair, hat etc. will prevent the heat from dissipating, leading to inaccurately high readings.

Ear (Tympanic) Thermometers

Ear thermometers measure temperature by detecting infrared heat emitted from the eardrum (tympanic membrane). Their advantages include:

• Quick Readings: Ear thermometers provide very rapid temperature readings, often in just a few seconds.
• Easy for Children: They are generally convenient for taking temperature in children, who might be less cooperative with other methods.
• Common and Accessible: Electronic ear thermometers are widely available and easy to purchase.

However, ear thermometers also have limitations:

• User-Dependent Accuracy: They require precise positioning in the ear canal to accurately read the eardrum’s temperature. Incorrect placement can lead to inaccurate results, especially in young children and infants, who have smaller ear canals.
• Interfering Factors: The presence of earwax or an ear infection can significantly affect the accuracy of readings.
• Variability: Temperature readings can vary slightly between the left and right ear due to individual variations or the presence of dirt or earwax.
• Not Always as Reliable as Probe: While easy to use, some users report less accuracy compared to probe thermometers.

The Verdict

While ear thermometers are quick and convenient, forehead thermometers generally provide more consistent and accurate readings when used correctly. The technology used in forehead thermometers targets a major artery, providing a more direct measure of core body temperature. Additionally, they are less susceptible to variations related to ear canal size, earwax, and user technique that can affect ear thermometers.

Frequently Asked Questions (FAQs)

1. Is it Better to Take Temperature on Forehead or Ear?

For most situations, a forehead thermometer is preferred for its accuracy and ease of use. Ear thermometers are an acceptable alternative, but require more careful use to ensure reliable readings.

2. What is Considered a Fever in Adults Using an Ear Thermometer?

Generally, a rectal, ear, or temporal artery temperature of 100.4°F (38°C) or higher indicates a fever in adults.

3. Can an Ear Thermometer Give a False High Reading?

Yes, ear thermometers can give false high readings if not placed correctly in the ear canal. The presence of earwax or an ear infection can also cause inaccurate readings.

4. Is a Touchless Thermometer More or Less Accurate Than an Oral Thermometer?

Touchless thermometers, typically forehead thermometers, can be less accurate than oral thermometers when used improperly, but when used correctly are similar in accuracy to probe thermometers. Oral thermometers are accurate when placed properly under the tongue, however they are more invasive and are not suitable for some individuals.

5. Do Ear Temps Run Higher Than Oral Temps?

Yes, an ear (tympanic) temperature is typically 0.5°F (0.3°C) to 1°F (0.6°C) higher than an oral temperature. Conversely, a forehead temperature is typically lower than an oral temperature.

6. Why Do Ear Thermometers Give Different Readings?

Ear thermometer readings can vary due to the positioning of the probe tip, individual differences, and the presence of earwax or infection in the ear canal.

7. Do Forehead Thermometers Add a Degree?

No, forehead thermometers typically read about 0.5°F to 1°F lower than an oral thermometer. So, you would add 0.5 to 1 degree to get what your temperature would read orally. For example, a 98.5°F forehead reading might be equivalent to a 99.5°F or higher oral temperature.

8. What is a Normal Forehead Temperature?

While the standard “normal” temperature is 98.6°F (37°C), normal forehead temperatures can range from 97°F (36.1°C) to 99°F (37.2°C).

9. Which Thermometer is No Longer Recommended for Use?

Glass mercury thermometers are no longer recommended due to the risk of mercury exposure if the thermometer breaks.

10. How Accurate is an Ear Thermometer?

While convenient, a study showed that ear thermometers may have a lower ability to detect fever compared to temporal thermometers (forehead). The study found the ear thermometer had an Area Under the Curve (AUC) of 0.972 while the temporal thermometer had an AUC of 0.931, indicating ear thermometers slightly better.

11. What is Considered a Low-Grade Fever?

A person with a temperature of 99.6°F to 100.3°F has a low-grade fever. A temperature of 100.4°F or higher is generally considered a fever.

12. Where Should I Aim My Forehead Thermometer?

Point the thermometer at the end of the person’s right eyebrow. Hold the thermometer at a length of 3 fingers (3-5 cm) away from the temple, ensuring it doesn’t touch the skin.

13. Why is My Temperature Different on Each Side of Forehead?

Temperature variations on each side of the forehead can result from head coverings, hair, or a pillow affecting heat dissipation. Sweating can also cause the temperature on the neck behind the ear to become the overriding reading.

14. Can Your Body Have a Fever but Not Your Forehead?

Yes, your body can have a fever while your forehead might not feel feverish. This is why relying on the “hand-on-the-forehead” method alone is not a reliable way to detect a fever.

15. Is 99.5 Considered a Fever?

While it might be a mild elevation, a temperature of 99.5°F is not generally considered a fever in adults. Healthcare providers often consider a body temperature of 100.4°F or higher as a fever in adults. However, infants and children are considered to have a fever if they have an oral temperature of 99.5°F or a rectal temperature of 100.4°F.

Conclusion

While both ear and forehead thermometers have their places, forehead thermometers emerge as the more reliable option for accurate temperature readings due to their direct arterial measurement and fewer potential sources of error. Always follow the manufacturer’s instructions carefully to ensure accurate results, and consult a healthcare professional if you have any concerns about your temperature readings.