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Pet Temperature Converter

Convert aquarium, room and water temperatures between Celsius and Fahrenheit.

✔ Vet reviewed · 18 Oct 2026Updated 18 Oct 2026Sources: Pure arithmetic / unit conversion on user inputs
Pet Temperature ConverterFree · instant
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Calculated in your browser. The numbers you type are never sent to us or stored.

Quick answer 25 °C is 77 °F, and 100 °F is about 37.8 °C. To convert Celsius to Fahrenheit, multiply by 9, divide by 5 and add 32; to convert back, subtract 32, multiply by 5 and divide by 9. This tool only converts units and gives no health advice.

How to use the pet temperature converter

  1. Enter the temperature.
  2. Choose Celsius or Fahrenheit.
  3. Press Calculate.

Worked example

An aquarium at 25 °C.

Temperature
25
Unit
Celsius (°C)
25 °C = 77 °F
Celsius
25 °C
Fahrenheit
77 °F

This only converts units and gives no health advice. If you are worried about your pet, contact your vet.

Example values are illustrative; this result is produced by the same calculator above.

How we calculate it

°F = °C × 9 ÷ 5 + 32; °C = (°F − 32) × 5 ÷ 9

Sources: Pure arithmetic / unit conversion on user inputs (no external constant)

Understanding your result

Aquarium heaters, thermometers and care guides use Celsius or Fahrenheit depending on the country. The converter uses the standard formulas: Fahrenheit equals Celsius times 9 divided by 5 plus 32, and Celsius equals Fahrenheit minus 32 times 5 divided by 9.

So 25 °C is 77 °F, and 100 °F is about 37.8 °C. Water freezes at 0 °C (32 °F) and the two scales meet at minus 40.

The tool converts units only. It cannot tell you what temperature is right for your fish, plants or animals, or whether a pet's body temperature is normal. Ask your vet or follow advice for your species.

Common mistakes

  • Reading a Fahrenheit thermometer as Celsius.
  • Rounding a conversion before checking a narrow temperature range.
  • Assuming a converted number is a safe temperature for your pet.
  • Forgetting that heaters can drift; check with a separate thermometer.
  • Using this to judge an unwell pet's temperature instead of calling a vet.

Good to know

  • Use the same unit on all your thermometers to avoid mistakes.
  • Check temperature at the same place and time each day.
  • The Aquarium Volume Calculator helps with other tank sums.

Frequently asked questions

How do I convert Celsius to Fahrenheit?

Multiply by 9, divide by 5 and add 32. 25 °C is 77 °F.

How do I convert Fahrenheit to Celsius?

Subtract 32, multiply by 5 and divide by 9. 100 °F is about 37.8 °C.

Is this for a pet's body temperature?

It only converts units. If you are worried about your pet's temperature or health, contact your vet.

What is 25 °C in Fahrenheit?

25 °C is 77 °F.

At what temperature are Celsius and Fahrenheit equal?

At minus 40 degrees, both scales read the same.

Can I use it for my pet's body temperature?

It only converts the numbers. If you are worried about your pet's temperature or health, contact your vet.

Reviewed by a licensed veterinarian
Last reviewed 18 Oct 2026 · How we review

Sources

  1. Pure arithmetic / unit conversion on user inputs (no external constant)
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Estimates only. Every pet is different — confirm with your veterinarian.