Using a thermometer is the best way to check your baby’s temperature. There are several different types of thermometers. Digital probe thermometers can be used in your child's mouth (orally) or under their armpit (axillary). In babies younger than 3 months old, it’s best to use this type of thermometer under their arm. Digital ear thermometers are quick and easy to use, but may give you less accurate readings if not used properly. These thermometers are recommended for children older than 3 months. Digital temporal artery thermometers use infrared scanning of your child's forehead. These thermometers are easy to use but not always accurate. Diagram showing different types of thermometers. Illustration showing different types of thermometers. Mercury thermometers are no longer recommended as they can break and poison your child. Fever strips and digital pacifier thermometers are also not recommended as they are not very accurate. Your doctor, nurse or pharmacist can show you how to use your thermometer properly. If your child’s forehead or skin feels very hot, it’s a good idea to use a thermometer to take their temperature accurately.