Celsius to Fahrenheit Calculator

Converting Celsius to Fahrenheit is straightforward once you know the steps. The two scales don't share the same starting point or the same degree size, so you can't just swap numbers directly. You need a small calculation.

Here's the basic process:

1. Take your temperature in Celsius.
2. Multiply it by 9, then divide by 5 (or just multiply by 1.8, same thing).
3. Add 32 to the result.

That's it. Three steps and you're done. For quick mental math, a rough shortcut is to double the Celsius temperature and add 30. It won't be exact, but it gets you close enough for casual use.

The official formula looks like this:

°F = (°C × 9/5) + 32

You can also write it as °F = (°C × 1.8) + 32 since 9 divided by 5 equals 1.8. Both versions produce the same answer.

The reason for the 9/5 multiplier is that a single Fahrenheit degree is smaller than a single Celsius degree. It takes 180 Fahrenheit degrees to span the same range that 100 Celsius degrees cover (from freezing to boiling water). The ratio 180/100 simplifies to 9/5. The +32 accounts for the offset between the two scales, since water freezes at 0°C but 32°F.

Notice that -40 is the one temperature where both scales agree exactly. That's not a coincidence; it's just where the math lines up.

Some temperatures come up over and over in daily life. Here are the ones worth having memorized:

• 0°C = 32°F — Water freezes. A key reference point.
• 10°C = 50°F — A cool, jacket-worthy day.
• 20°C = 68°F — Comfortable room temperature.
• 22°C = 71.6°F — The sweet spot most people call "room temp."
• 37°C = 98.6°F — Normal human body temperature.
• 100°C = 212°F — Water boils at sea level.
• 180°C = 356°F — A common baking temperature for moderate oven heat.
• 200°C = 392°F — A hot oven setting used for roasting.

The body temperature one (37°C / 98.6°F) is particularly handy to know. If you're reading a medical thermometer that shows Celsius, 37°C means you're normal. Anything noticeably above that and it's worth paying attention.

Both scales measure the same physical thing, temperature, but they were built around different reference points and have different sized degrees.

Celsius (also called centigrade) was designed to be clean and logical. Zero is freezing, 100 is boiling. Easy to anchor. Fahrenheit, developed by Daniel Gabriel Fahrenheit in the early 1700s, used different reference points, including the temperature of a saltwater ice mixture and human body heat. It ended up with finer gradations, which some argue is useful for describing everyday weather in more detail.

Scientists worldwide use Celsius, and in many cases Kelvin, which starts at absolute zero and uses the same degree size as Celsius. But for daily weather and cooking, it really just depends on where you grew up.

Temperature conversions aren't just an academic exercise. There are plenty of practical situations where you'll actually need them.

• Cooking and baking: Recipes from European and Australian cookbooks almost always list oven temperatures in Celsius. If your oven is calibrated in Fahrenheit, you need to convert or you risk over- or under-cooking your food.
• Travel: Checking the weather for a trip to Europe, Canada, or pretty much anywhere outside the U.S. means reading Celsius forecasts. Knowing that 25°C is a warm, pleasant 77°F helps you pack appropriately.
• Health and medicine: Fever thresholds, medication storage temperatures, and lab results may be reported in either scale depending on the source.
• Science and engineering: Technical documents, material specifications, and international standards typically use Celsius (or Kelvin). American engineers working with global partners often need to convert back and forth.
• Home appliances: Some imported appliances or smart thermostats may default to Celsius. Knowing how to interpret those readings saves a lot of confusion.

In short, if you interact with the wider world in any meaningful way, knowing how to move between these two scales is a practical skill, not just a math curiosity.

Let's walk through a few real calculations using the formula °F = (°C × 1.8) + 32.

Example 1: Convert 25°C to Fahrenheit

1. 25 × 1.8 = 45
2. 45 + 32 = 77°F

A warm, sunny day by any measure.

Example 2: Convert 0°C to Fahrenheit

1. 0 × 1.8 = 0
2. 0 + 32 = 32°F

Exactly at the freezing point. Makes sense.

Example 3: Convert 37°C to Fahrenheit

1. 37 × 1.8 = 66.6
2. 66.6 + 32 = 98.6°F

Normal body temperature, confirmed.

Example 4: Convert -10°C to Fahrenheit

1. -10 × 1.8 = -18
2. -18 + 32 = 14°F

That's cold. Bundle up.

Once you've done a few of these by hand, the formula becomes second nature. And when you just need a quick answer, the calculator at the top of this page handles it in a second.