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American travelers, this one is for you! This piece explains how to convert Celsius to Fahrenheit quickly when you’re traveling abroad. As a bonus, we’ve even thrown in some quick ways to convert kilometers to miles. Enjoy!

Raise your hand if you’ve been in this situation: You’re on vacation in another country. You wake up in your hotel after a restful sleep, and you start thinking about how you’d like to spend your day. Will you hit the beach, head out for a hike, or visit a museum?

If  you’re like me, your choice might depend on the weather. I mean, nobody wants to go to the beach in the rain or hike on a scorcher of a day, right? So, you turn on the TV or open your phone’s weather app to check the forecast and…hmmm…that can’t be right. It’s only 27 degrees?!?

Right about then, it probably dawns on you that you’re not dealing with freezing temperatures. Instead, you’re dealing with that pesky metric system.

The Metric System

Why oh, why oh, why oh would anybody ever use the darn metric system?

Well, according to Wikipedia, the metric system is “an internationally adopted decimal system of measurement.” The key phrase here is “internationally adopted.” As in, basically every country in the world uses it.

But not us! Here in America, we’re stubborn. We do things our own way, and in this shining city on a hill, we’re still holding out hope that the old way of measuring weight, distance, and temperature will prevail!

Unfortunately for Americans, that battle has been lost. The international community has spoken, and they all agree that the metric system is the way to go. This also means we’re out of sync with the rest of the world when it comes to measurements.

While we still think in terms of degrees Fahrenheit, feet, inches, pounds, and miles, people living in countries that use the metric system don’t. Instead, they use degrees Celsius, meters, centimeters, kilograms, and kilometers.

This might not seem like a big deal, but – when you’re traveling – being unable to understand the forecast, the speed limit, or the distance to your destination can get old pretty fast. Not to mention, it can also be super embarrassing if it comes up in a conversation with the locals. I mean, you don’t want to be visiting Dublin and be unable to hold a conversation, do you? The weather is the universal topic of small talk, after all.

Luckily, we’ve put together this handy guide for converting degrees Celsius to Fahrenheit and kilometers to miles.

Quick and Dirty Celsius to Fahrenheit Conversions

Trust me, when our family is traveling to the Loire Valley in France, being the dumb Americans who can’t gauge the temperature kind of sucks. Thankfully, that no longer has to be you.

If you don’t have your phone, a calculator, or a computer handy, use this quick formula to estimate the Celsius to Fahrenheit conversion:

Celsius Temperature x 2 + 30 = Approximate Fahrenheit Temperature

Pretty easy, right?

For example, if you’re checking the weather and it says 27 degrees Celsius, that’s 27 x 2 = 54 + 30 = 84. So, 27 degrees Celsius is approximately 84 degrees Fahrenheit. In other words, it’s a pretty warm day.

Keep in mind, this is only an estimate. As the temperature grows warmer, the formula becomes less accurate. But hey, you’re not reporting the weather; you’re just trying to interpret the forecast and not feel like an idiot. So, for your purposes, this formula will work just fine.

Celsius to Fahrenheit: The Real Deal

If you want to be precise, the actual formula for converting Celsius to Fahrenheit is this:

Celsius Temperature x 1.8 + 32 = Fahrenheit Temperature

So, if we go back to our 27 degrees Celsius example, we get:

27 x 1.8 = 48.6 + 32 = 81

Thus, 27 degrees Celsius is actually equal to 81 degrees Fahrenheit. You can see how this is a bit off from our estimate of 84 degrees, but it’s in the general ballpark.

For reference, the following table shows a range of Celsius temperatures and their Fahrenheit counterparts. So, the next time you’re looking for things to do in London, you can use this handy little chart to decide if the weather will permit it. We’ve started the table at -40 °C and went up to 40 °C – let’s hope you aren’t vacationing in any temperatures more extreme than those!

Celsius to Fahrenheit Conversion Table (Rounded to Whole Degrees)

Kilometers to Miles on the Fly

Now that you understand the Celsius to Fahrenheit conversion, let’s move on to converting distance and speed.

Just like converting temperature, not understanding speeds and distance can be a problem for Americans when traveling.

Let me say this: The speed limit on Canadian highways is definitely not 100 miles per hour (mph). 100 kilometers (km) per hour is a whole different thing, and works out to be about 62 mph. Mixing that up means you’ll likely have problems with law enforcement. I don’t know about you, but I can’t think of a faster way to put a damper on a vacation than by getting a ticket. (Extra points if you caught that pun…)

Even if you’re not driving, it’s useful to understand just how far a km is. If someone tells you a destination is 5 km away, you need to be able to assign meaning to that.

Here are a couple of quick tricks for quickly converting km to miles:

5 miles = 8 km

For example, 50 miles = 80 km. So, if you see a speed limit sign that says 100 km per hour, it means about 60 mph.

How do we get those numbers? If you’re converting km to miles, you want to divide the km by 8 and multiply by 5. So, 100/8 = approximately 12, multiplied by 5 = 60.

If you’re going from miles to km, you’ll need to divide by 5 and multiply by 8. It’s not precise, but it’s close enough.

Here’s another rough estimate:

Km divided by five and then multiplied by 3 = Approximate miles

For example, 75 km/5 = 15 x 3 = 45 miles

If you want to convert miles to km, you simply reverse it. Divide the miles by 3 and multiply by 5 to get your answer.

Again, this isn’t precise, but it’s fine for a quick estimate.

Km to Miles: The Real Deal

If you wanna get nitpicky about it, 1 km is actually equal to 0.621 miles. So, to convert km to miles, you just need to multiply it by 0.621. Now, if you can do that in your head on the fly, you’re a lot better at math than I am!

On the other hand, if you’re not a superhuman math wiz, here’s a table with (almost) exact km to miles conversions that you can use for reference.

Km to Miles Conversion (Rounded to One Decimal Place)

Metric Conversions for Travel: Final Thoughts

So, there you have it – one quick way to convert Celsius to Fahrenheit and two easy ways to convert kilometers to miles. Just in case you need to be a bit more exact, you’ve also got the real formulas and corresponding reference tables.

Most importantly, the next time you’re in Switzerland (or any other part of the world), you don’t have to worry about being that clueless American who can’t navigate the darn metric system. You’re welcome 😉

Do you have a fast way to convert Celsius to Fahrenheit we didn’t cover? Let us know in the comments below! 

Fahrenheit and celsius temperature conversion

Converting from Fahrenheit to Celsius

From the mid-18th to mid-20th centuries, Fahrenheit was the system most widely used in English-speaking countries, while continental Europeans preferred 'The Swedish Scale'. With the drive to standardisation and metrication from the 1950s, Celsius became the adopted temperature scale for the EEC (later EU), with the UK and Ireland converting (somewhat reluctantly) after joining the European community.

This reluctance was partly due to human preference. For while the Celsius scale was developed for convenience, Fahrenheit's scale was based on observation and measurement. Also, whereas Fahrenheit had developed a ratio scale, Celsius had produced an interval scale. These are very different things, as we shall explain in a future article.

This may help explain why many people prefer Fahrenheit readings as rather closer to actual experience. In Celsius, a chilly day at 11°C does not seem greatly different from a really hot one at 35°C. On the Fahrenheit scale, these respectively measure at about 52°F and 95°F, with the latter traditionally taken as license for red top tabloids to start running 48 point headlines containing words like 'Phew', 'Flaming' and 'Scorcher'.

Incidentally, while the UK's Met Office started publishing temperatures in both Celsius and Fahrenheit from 1962 and dropping use of Fahrenheit altogether from official reports in 1970, British media persisted in using Fahrenheit in weather reports well into the 21st century. Indeed it became the fashion to use Celsius when describing extreme winter conditions and Fahrenheit for heat waves - a nice example of double standards in action.

Fahrenheit and Celsius formula

The formula to convert Fahrenheit to Celsius is:

[°C] = ([°F] - 32) × 5/9


In other words, take your Fahrenheit reading, subtract 32, multiply the answer by five and then divide by nine. So 66 degrees Fahrenheit minus 32 would be 34, times five makes 170 divided by nine equals 18.88 recurring, or 18.9°C.

Celsius and Fahrenheit formula

[°F] = [°C] × 9/5 + 32

Here, you multiply your Celsius temperature by nine, divide by five and then add 32 to find the Fahrenheit reading.

So, 13 degrees Celsius times nine is 117, divided by five is 23.4, plus 32 makes 55.4°F.

Using decimals

To make life a little simpler, using decimals instead of fractions, you can use 1.8 instead of 9/5.

This gives the following modified formulae

Trying this out in action on a hot day (and remembering that multiplying by 1.8 is the same as doubling and then subtracting 10 per cent) we could have 36°C plus 40 is 76, times 1.8 is 136.8 minus 40 is 96.8°F, which is firmly in 'Scorcha' territory.

And the other way, on a rather chillier day, 48°F plus 40 is 88, divided by 1.8 is 48.88 recurring (48.9) minus 40 equals 8.9°C, which actually does sound quite cold.

Fahrenheit to Celsius reference chart

Celsius readings rounded up or down to single decimal points.

Celsius to Fahrenheit reference chart

Fahrenheit readings rounded up or down to nearest whole degree

Conversion units for the Temperature Converter

Celsius or Centigrade, Fahrenheit, Kelvin, Rankine, Reamur,

If you are cooking or baking, take a look at our charts for oven temperature conversions.

To help with productivity, we now set a cookie to store the last units you have converted from and to. This means that when you re-visit this temperature converter, the units will automatically be selected for you.

Enter the value of the temperature you would like to convert and select its unit. Then select the unit you want to convert to.

How to Convert Celsius to Fahrenheit

1. Take the temperature in Celsius and multiply 1.8
2. Add 32 degrees
3. The result is degrees Fahrenheit.

How to Convert Fahrenheit to Celsius

1. Take the temperature in Fahrenheit subtract 32
2. Divide by 1.8
3. The result is degrees Celsius

How to Convert Celsius to Kelvin

K = C + 273.15

Where K = Degrees in Kelvin and C = Degrees in Celcius

The Celsius and Kelvin scales use the same size degrees, but Kelvin has a zero point at absolute zero, not the freezing point of water. So Kelvin temperatures have values 273.15 degrees higher than the same temperature in Celsius.

Example : the boiling point of water is 100 °C , which is equal to 373.15 K

The Kelvin scale is based on the concept of Absolute Zero, the temperature at wich matter stops vibrating. This temperature is -273.15 °C.

Common Temperature Conversions

Convert Degree Celsius (°C) to…

• 1 degree Celsius (°C) = 33.8 degree Fahrenheit (°F)
• 1 degree Celsius (°C) = 274.15 Kelvin

Convert Degree Fahrenheit (°F) to…

• 1 degree Fahrenheit (°C) = -17.222* degree Celsius (°C)
• 1 degree Fahrenheit (°C) = 255.928* Kelvin

Convert Kelvin to…

• 0 Kelvin = -273.15 degree Celsius (°C)
• 0 Kelvin = -459.67 degree Fahrenheit (°F)

* Calculation to 3 decimal places

In every science class, you must know how to use and interpret the Celsius temperature scale. But this can be difficult for students who are used to using Fahrenheit instead. How do you convert Celsius to Fahrenheit? What about Fahrenheit to Celsius?

We answer these questions below, giving you the mathematical formulas for converting between these two temperature units, a handy conversion chart, and a quick conversion trick you can use without having to grab a calculator.

Celsius vs Fahrenheit: Key Differences

Before we explain how to convert Celsius to Fahrenheit (and Fahrenheit to Celsius), let’s review the main differences between the two temperature scales.

Celsius (written as °C and also called Centigrade) is the most common temperature scale in the world, used by all but five countries. It’s part of the International System of Units (SI), or what you might know as the metric system, which is typically used in science classes (think centimeters, meters, kilograms, milliliters, etc.) and in science as a whole.

By contrast, Fahrenheit (written as °F) is only used officially by five countries in the world:

• United States
• Belize
• Cayman Islands
• Palau
• Bahamas

Fahrenheit is not part of the metric system; rather, it’s part of the Imperial system, which includes forms of measurements such as inches, feet, pounds, gallons, etc. Moreover, unlike Celsius, it is not typically used in science.

Celsius to Fahrenheit Formula

Unfortunately, converting from Celsius to Fahrenheit isn’t easy to do quickly or in your head. Here are the formulas used to convert Celsius to Fahrenheit and Fahrenheit to Celsius. These formulas will give you the exact conversion from one unit of temperature to the other:

Celsius to Fahrenheit Formula: (°C * 1.8) + 32 = °F

Fahrenheit to Celsius Formula: (°F - 32) / 1.8 = °C

For example, say the temperature outside is 18 °C and you want to know what this would equal in Fahrenheit. Here’s how your equation would look once you plug in 18 for °C:

(18 * 1.8) + 32
(32.4) + 32
=64.4 °F

Here’s another example if you want to convert Fahrenheit to Celsius: say you’re feeling ill and your body temperature is 101.3 °F. To find out what this equals in Celsius, simply plug 101.3 into the °F part in the second equation written above:

(101.3 - 32) / 1.8
(69.3) / 1.8
=38.5 °C

As you can see, these conversions aren’t particularly hard to carry out, but they do take some time and aren’t the easiest to do without a calculator on hand.

Luckily, there’s a shortcut. By memorizing some of the most common temperatures that come up in daily life, you should have no problem being able to convert from Celsius to Fahrenheit and vice versa. We’ll take a look at how to do this next.

It's gettin' hot in here.

Celsius to Fahrenheit Conversion Chart

Below is a conversion chart listing some of the most commonly used temperatures in everyday life when converting from Celsius to Fahrenheit. Memorize these and you’re sure to have an easier time converting from Celsius to Fahrenheit (and vice versa) fast.

Note: I’ve bolded all temperatures that don’t apply to weather but are still important to know, especially for science class.

Source: NIST.gov

*The point at which the two temperature units are equivalent (-40 °C = -40 °F).

As you can see from this chart, Fahrenheit temperatures are typically a lot higher than their equivalent Celsius temperatures are.

Also, notice how the difference between Celsius and Fahrenheit starts to get smaller the lower you go in temperature—until, that is, they're the exact same! As the chart indicates, -40 °C is the same temperature as -40 °F.This point is called parity, meaning the two scales use the same value to represent the same temperature. Unfortunately (or fortunately, since this is pretty cold!), you likely won’t come across this temperature in your daily life.

Note that parity only happens at -40°. The lower you go after parity (i.e., the further you go into the negatives), the bigger the difference starts to become again between Celsius and Fahrenheit.

How to Convert Celsius to Fahrenheit: Quick Trick

If you find yourself needing to quickly convert Celsius to Fahrenheit, here is a simple trick you can use: multiply the temperature in degrees Celsius by 2, and then add 30 to get the (estimated) temperature in degrees Fahrenheit. This rule of thumb is really useful and also pretty accurate for most weather-related temperatures.

For example, if the temperature outside is 15 °C, this would come out to around 60 °F:

(15 * 2) + 30
(30) + 30
=60 °F (In reality, 15 °C is equivalent to 59 °F—that’s pretty close!)

Of course, expect the actual temperature to be a few degrees off, but for the most part, this is a reliable and easy way to convert temperatures in your head fast.

If you want to convert Fahrenheit to Celsius, do the opposite: subtract 30 from the temperature in degrees Fahrenheit, and then divide by 2 to get the temperature in degrees Celsius.

For example, if the temperature outside is 84 °F, this would be roughly equal to 27 °C:

(84 - 30) / 2
54 / 2
= 27 °C (In reality, 84 °F is equivalent to 28.89 °C—again, that’s a pretty close estimate!).

What’s Next?

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