What's the Most Accurate Way to Take a Baby's Temperature at Home?
The most accurate way to take a baby's temperature at home is with a digital thermometer held in the armpit (the underarm, or axillary, method). For babies under three months especially, this is the reading Australian health services rely on. Ear (tympanic) thermometers are accurate and quick for babies over six months, while forehead and touchless thermometers are handy for a fast everyday check — just confirm anything that worries you with an underarm reading.
Here's how to take your baby's temperature properly, which method suits which age, and when a reading means it's time to call a doctor.
What counts as a fever in a baby?
A temperature of 38°C or higher is generally considered a fever. What matters most, though, is how your baby is behaving — a slightly raised temperature in a happy, feeding baby is less worrying than a normal reading in a floppy, unusually drowsy one. If your baby is under three months old and has a temperature of 38°C or above, see a doctor straight away, even if there are no other symptoms.
The most accurate method: a digital thermometer under the arm
For babies and young children, a digital thermometer placed in the armpit gives a reliable reading and is the method most often recommended in Australia. According to Raising Children Network, digital thermometers are safe, accurate and easy to use at home.
How to take an underarm temperature
Sit your baby on your lap. Tuck the tip of the thermometer into the centre of a dry armpit, then gently hold their arm against their body so the tip is fully covered by skin. Wait for the beep, then read the number. Take it when your baby is calm rather than mid-cry, and not straight after a warm bath or a big cuddle under blankets, as those can nudge the reading up.
Ear thermometers: fast and accurate for older babies
Digital ear (tympanic) thermometers measure the temperature inside the ear canal in about a second, which is a real advantage with a wriggly baby. They're accurate when positioned correctly, and are best suited to babies aged six months and older — a young baby's ear canal is very small, which can make the reading less reliable. Always follow the instructions and make sure the probe points correctly into the canal.
Forehead and touchless thermometers: convenient for quick checks
Forehead (temporal) and no-touch infrared thermometers are popular because you can check a sleeping baby without disturbing them. They're brilliant for a quick, gentle screening — a nightly "is she warm?" check. Keep in mind they can be affected by things like a sweaty forehead, a draughty room or incorrect distance, so if a forehead reading suggests a fever, it's worth confirming with an underarm digital reading before you act on it.
One thermometer, several ways to check
Cherub Baby's 4-in-1 Infrared Ear & Forehead Thermometer gives you a quick ear reading for babies over six months and a gentle touchless forehead check for sleeping littlies — ideal for everyday monitoring alongside a digital underarm reading when you need to confirm a fever. View Product →
Browse the full range in our baby thermometer collection or stock up on newborn feeding & health essentials.
Methods to avoid
Some tools simply aren't reliable enough to trust with a baby's health. Plastic forehead strip thermometers, dummy (pacifier) thermometers and smartphone "thermometer" apps can all give inaccurate readings and aren't recommended. Old glass mercury thermometers should never be used, as they can break and release toxic mercury.
Which method by age, at a glance
- Newborn to 3 months: digital thermometer under the arm; see a doctor for any fever of 38°C or more.
- 3 to 6 months: digital underarm reading is still the most reliable; touchless forehead is fine for quick checks.
- 6 months and older: ear (tympanic) thermometers become a fast, accurate option; underarm and forehead still work well.
Tips for a reliable reading
Read the instructions that came with your thermometer before the first use — every model differs slightly. Keep the tip and lens clean. Take the temperature when your baby is settled, not overheated from crying, feeding or bundling. And if you're ever unsure how to use your thermometer, your GP, pharmacist or child and family health nurse can show you.
When to see a doctor
Call your doctor or health service if your baby is under three months with a temperature of 38°C or higher; if an older baby has a fever that lasts more than a day or two; or at any age if your baby seems very unwell, is hard to wake, is breathing quickly, has a rash that doesn't fade under pressure, or you simply feel something isn't right. Trust your instincts — you know your baby best.
Frequently asked questions
What is the most accurate way to take a baby's temperature?
A digital thermometer held in the armpit is the most reliable method for babies, and the one most recommended in Australia. For babies over six months, a correctly positioned ear thermometer is also accurate and much faster.
Are forehead thermometers accurate for babies?
Forehead and touchless thermometers are convenient for quick checks but can be thrown off by sweat, room temperature or distance. If a forehead reading suggests a fever, confirm it with an underarm digital reading.
What temperature is a fever in a baby?
A reading of 38°C or higher is generally considered a fever. In a baby under three months, any fever should be checked by a doctor straight away.
Can I take my newborn's temperature in the ear?
Ear thermometers are best for babies aged six months and over, as a newborn's ear canal is too small for a reliable reading. For newborns, use a digital thermometer under the arm.
Should I add a degree to an underarm reading?
No. Read the number your digital thermometer shows and follow the instructions that came with it. If you're unsure, your GP or child and family health nurse can guide you.
Why does my baby's temperature change through the day?
Body temperature naturally rises and falls a little across the day and can lift after feeding, crying or being wrapped up warmly. Take a reading when your baby is calm and not overheated for the most accurate result.
