First aid & emergency
Best pet thermometer: how to choose and how to use it
A pet thermometer is one of the cheapest and most useful items in a UK pet first aid kit. Knowing whether your dog or cat is running a fever, hypothermic, or in heat stroke is information your vet wants the moment you phone. This guide covers the three main thermometer types, what works in practice, and what to skip.
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What to look for
- A standard digital rectal thermometer — the most accurate option for dogs and cats. Reads in 10–30 seconds.
- Flexible tip rather than rigid — kinder to use and less likely to cause discomfort or injury.
- Beep on completion — important when you're holding a wriggling pet with one hand.
- Backlit display — for low-light situations, e.g. evening emergencies.
- Easy-to-clean smooth surface — gets disinfected after every use.
- Suitable temperature range — pet temperatures peak around 41°C in fever; some human thermometers max out lower.
What to avoid
- Non-contact infrared thermometers marketed for pets — accuracy is poor through fur and skin compared to rectal readings. Useful as a rough screening tool only.
- Ear thermometers for dogs and cats — placement matters, accuracy is variable, and they're expensive for the result. Vet practices use them but with training.
- Strip thermometers and 'forehead' thermometers — not reliable for pets.
Our recommendations
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Digital pet rectal thermometer (flexible tip)
The accurate, reliable choice. £5–15 in most UK pet shops or on Amazon. Lubricate with a smear of petroleum jelly, insert about 2cm for cats and small dogs, 3cm for larger dogs.
View on Amazon → -
Standard digital thermometer (human, fast-read)
Works fine for pets if you keep it dedicated to pet use. Look for under-30-second read times — anything slower is a struggle with a wriggling pet.
View on Amazon → -
Petroleum jelly (Vaseline)
A small tub kept in the first aid kit for thermometer lubrication and minor paw-pad protection. Pet-safe and lasts forever.
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Non-contact infrared thermometer (for screening only)
Useful as a quick screening tool — wave over the inside ear or armpit. Don't rely on it for accurate readings; confirm anything concerning with the rectal thermometer.
View on Amazon →
Frequently asked questions
What is a normal temperature for a dog or cat?
38.3–39.2°C (101.0–102.5°F) for both species. Above 40°C is concerning; above 41°C is an emergency. Below 37.2°C in a sick or injured pet is also concerning — possible shock or hypothermia.
How do I take my pet's temperature without help?
With a small dog or cat, sit them on your lap or wrap in a towel with the back end accessible. With a larger dog, kneel beside them and have them stand. Lubricate the tip, lift the tail, insert gently, hold until it beeps. Treats afterwards make next time easier.
Can I use the same thermometer on humans afterwards?
Don't. Keep the pet thermometer dedicated to pet use, label it clearly, and store it in the first aid kit.