What Is an Oral Temperature?
Taking an oral temperature means placing a thermometer under the tongue to measure body temperature. This method is accurate, convenient, and the most common way to check temperature in older children, teenagers, and adults. It provides a reliable core body temperature reading when done correctly.
Oral temperatures are suitable for children who are old enough to understand how to keep their mouth closed around the thermometer and not bite it—typically around age 4 or 5, though some children can manage it younger. The key requirement is that the child can follow instructions and keep the thermometer safely under their tongue.
📌 Key Point: An oral temperature of 100°F (37.8°C) or higher is considered a fever. Oral readings are typically about 0.5°F lower than rectal readings but higher than axillary (armpit) readings.
When to Use Oral Temperature
✅ Best For:
- • Children age 4-5 and older
- • Kids who can follow instructions
- • Routine temperature checks
- • Monitoring known illness
- • When child prefers it over other methods
- • Quick, convenient readings
❌ Not Appropriate For:
- • Infants and toddlers (can't follow instructions)
- • Children with mouth injuries or sores
- • Recent oral surgery or dental work
- • Child who has difficulty breathing through nose
- • Very young children who might bite thermometer
- • Immediately after eating/drinking hot or cold items
What You'll Need
Simple Supplies
- ✓ Digital thermometer (oral type or multi-use)
- ✓ Disposable probe covers (optional)
- ✓ Pen and paper to record temperature
Important: Don't use glass or mercury thermometers. Digital thermometers are safer, faster, and easier to read. If you use the same thermometer for different methods, clean it thoroughly between uses or use disposable probe covers.
Step-by-Step Instructions
Wait After Eating/Drinking
Wait 15-30 minutes after your child has eaten or drunk anything (especially hot or cold items) before taking an oral temperature. Food and beverages affect mouth temperature.
Prepare the Thermometer
- • Wash thermometer with soap and cool water
- • Rinse thoroughly and dry
- • Turn on the thermometer
- • Wait for "ready" signal
- • Apply disposable probe cover if using
Position the Thermometer
Place the thermometer tip under your child's tongue:
- • Position it in one of the "heat pockets" on either side of the tongue (not on top of tongue)
- • The pockets are the areas under the tongue, close to where it connects to the floor of mouth
- • This is where blood vessels bring heat from the body's core
💡 Tip: Show your child where to place the thermometer before starting. You can practice with the thermometer turned off.
Close the Mouth
- • Have child close lips around thermometer
- • Lips should seal gently but completely
- • Don't bite down on thermometer
- • Hold thermometer in place with lips, not teeth
- • Breathe through nose, not mouth
Keep Still and Quiet
- • Sit or stand still during reading
- • No talking while thermometer is in mouth
- • Stay quiet and relaxed
- • Wait for the thermometer to beep
Wait for Signal
Most digital oral thermometers beep after 10-30 seconds. Don't remove until you hear the signal, even if it feels like it's taking a while.
Remove and Read
- • Remove thermometer carefully
- • Read the digital display
- • Write down temperature and time
- • Note if reading is 100°F (37.8°C) or higher
Clean and Store
- • Wipe with clean tissue
- • Wash with soap and lukewarm water
- • Can clean with rubbing alcohol
- • Dry and return to protective case
- • Store in clean, dry place
Understanding Oral Temperature Results
✅ Normal Range
Oral: 97.6°F to 99.6°F (36.4°C to 37.5°C)
Note: Normal body temperature varies slightly by person and time of day (usually lowest in early morning)
⚠️ Low-Grade Fever
Oral: 99.7°F to 100°F (37.6°C to 37.8°C)
🔴 Fever
Oral: 100°F (37.8°C) or higher
Temperature Comparison Chart:
Rectal
100.4°F = Fever
Oral
100°F = Fever
Axillary
99°F = Fever
Tips for Accurate Oral Readings
⏰ Timing Matters
- • Wait 15-30 minutes after eating/drinking
- • Wait after chewing gum or sucking candy
- • Wait after smoking (for teens)
- • Even ice water can affect reading for 15 minutes
📍 Proper Placement
- • Under tongue, in heat pocket
- • Not on top of tongue
- • Not in front of mouth
- • Position is crucial for accuracy
🤐 Seal the Lips
- • Lips must be completely closed
- • No air gaps
- • Breathe through nose only
- • Don't talk
🎯 Explain to Child
- • Show them what to do
- • Explain why it's important to stay still
- • Make it a game for young kids
- • Praise cooperation
Teaching Your Child to Take Their Own Temperature
Older children and teens can learn to take their own oral temperature:
Age 7-10: With Supervision
- • Teach proper technique step by step
- • Supervise each time to ensure accuracy
- • Help with reading and recording
- • Check their placement is correct
Age 11+: Independent
- • Most can do it independently
- • Remind about waiting after eating/drinking
- • Have them report the reading to you
- • Periodically verify their technique
Troubleshooting Common Problems
Problem: Child keeps opening mouth
Solution: Remind them to keep mouth closed. Count down the seconds out loud so they know how much longer. For young children, distract with a video or book while holding thermometer.
Problem: Child wants to bite thermometer
Solution: Explain they should hold it gently with lips, not teeth. If they can't resist biting, they may not be ready for oral temps—try axillary method instead.
Problem: Reading seems too low
Solution: Check that child didn't recently drink cold water. Ensure thermometer was under tongue (not on top) and mouth was closed entire time. Retake if needed.
Problem: Child has stuffy nose
Solution: If child can't breathe through nose, mouth breathing will cool the thermometer and lower the reading. Use axillary or ear thermometer instead.
Frequently Asked Questions
Q: What age is safe for oral temperatures?
Most children are ready around age 4-5, but it depends on the individual child's maturity and ability to follow directions. The child must be able to keep the thermometer under their tongue with mouth closed, not bite it, and stay still. If your child can't do this reliably, use another method.
Q: Is oral temperature as accurate as rectal?
Oral temperatures are quite accurate when taken correctly, though generally considered slightly less precise than rectal. For most purposes in older children, oral readings provide sufficient accuracy. The difference is clinically insignificant in routine situations.
Q: Can I use a regular thermometer for oral temps?
Yes, most digital thermometers can be used for multiple methods. However, if a thermometer has been used rectally, it should be labeled and reserved for rectal use only. Use a separate thermometer for oral readings or use disposable probe covers.
Q: Why do I get different readings each time?
Small variations (0.1-0.3°F) are normal. Body temperature naturally fluctuates throughout the day. Larger differences usually mean the thermometer wasn't positioned correctly, mouth wasn't fully closed, or reading wasn't complete. Also check if child recently ate or drank something.
⚠️ Medical Disclaimer
This article provides general information about taking oral temperatures and is not intended to replace professional medical advice. Always follow your pediatrician's specific instructions for temperature measurement and fever management. If you have concerns about your child's temperature or health, contact your healthcare provider.