Most of the world reads the weather in Celsius, the United States still reports it in Fahrenheit, and science works in kelvin. Sooner or later everyone has to translate between the three: a European recipe that says to bake at 180 degrees, a forecast on holiday, a chemistry result quoted in kelvin. This temperature converter does the translation instantly. Type any value, choose the scale it is measured in, and you will see the same temperature in Celsius, Fahrenheit and kelvin side by side, along with the formula that produced each answer. Below the tool you will find the formulas explained in plain language, worked examples, a full conversion table and the mistakes that catch people out most often.
Formula: 180 °C x 1.8 + 32 = 356 °F · 180 °C + 273.15 = 453.15 K
Quick reference (select a row to load it into the converter):
| Reference point | Celsius | Fahrenheit | Kelvin |
|---|---|---|---|
| Water freezes | 0 °C | 32 °F | 273.15 K |
| Human body temperature | 37 °C | 98.6 °F | 310.15 K |
| Water boils | 100 °C | 212 °F | 373.15 K |
The three temperature scales at a glance
Celsius is built around water. On this scale water freezes at 0 °C and boils at 100 °C at sea level, which is why most countries use it for weather, cooking and everyday life. Fahrenheit comes from an older scale devised in the early eighteenth century: water freezes at 32 °F and boils at 212 °F, and it remains the everyday scale in the United States. Kelvin is the scale of science. It uses exactly the same step size as Celsius, so a change of one kelvin equals a change of one degree Celsius, but it starts at absolute zero, the coldest temperature that can exist. Because kelvin measures from that absolute starting point, it is written as a plain unit with no degree symbol: 300 K, never 300 °K.
The reason temperature conversion needs more than a simple multiplier is that the scales disagree about two things at once: where zero sits and how big a degree is. Celsius and Fahrenheit differ on both counts, which is why the formula both multiplies and adds. Celsius and kelvin differ only in their starting point, so converting between them is a single addition or subtraction. Once you see that, every formula below falls into place.
Temperature conversion formulas
Every conversion between the three scales uses one of these relationships:
- Celsius to Fahrenheit: °F = °C x 1.8 + 32
- Fahrenheit to Celsius: °C = (°F - 32) / 1.8
- Celsius to kelvin: K = °C + 273.15
- Kelvin to Celsius: °C = K - 273.15
- Fahrenheit to kelvin: convert to Celsius first, then add 273.15
- Kelvin to Fahrenheit: convert to Celsius first, then multiply by 1.8 and add 32
The 1.8 is the fraction 9/5: between freezing and boiling, Celsius spans 100 degrees while Fahrenheit spans 180, and 180 divided by 100 is 1.8. The 32 corrects for Fahrenheit starting its count 32 degrees earlier. One curiosity worth remembering is -40: it is the single point where the Celsius and Fahrenheit scales agree, so -40 °C and -40 °F are exactly the same temperature.
Worked example: how to convert 180 °C to Fahrenheit
"Convert 180 celsius to fahrenheit" is one of the most common temperature searches on the internet, because 180 °C is the baking temperature printed in countless European and British recipes. Here is the calculation in full:
- Start with the Celsius value: 180.
- Multiply by 1.8: 180 x 1.8 = 324.
- Add 32: 324 + 32 = 356.
So 180 °C = 356 °F. On the kelvin scale the same temperature is 180 + 273.15 = 453.15 K. In practice, many American ovens are marked in 5 or 25 degree steps, so cooks often set 350 °F for a 180 °C recipe and accept a tiny difference. If your recipe gives a Gas Mark or talks about fan ovens, use our Oven Temperature Converter, which is dedicated to oven settings rather than general temperature conversion.
The reverse direction works the same way. To convert 98.6 °F to Celsius, subtract 32 to get 66.6, then divide by 1.8 to get exactly 37 °C, normal body temperature. The converter above handles both directions, and everything between, as you type.
How do you convert kelvin to Celsius?
This is the easiest conversion of the three because the two scales share the same degree size. To convert kelvin to Celsius, subtract 273.15. For example, 300 K - 273.15 = 26.85 °C, a warm day. Going the other way, to convert Celsius to kelvin, add 273.15: 25 °C + 273.15 = 298.15 K. Nothing is ever multiplied, which is exactly why scientists like the pairing.
Two reference points anchor the kelvin scale. Absolute zero, 0 K, is -273.15 °C, the point at which particles have the minimum possible energy. Water freezes at 273.15 K and boils at 373.15 K. Because kelvin can never be negative, it is the natural scale for physics, astronomy and any work with very cold temperatures, while Celsius stays more convenient for daily life because its numbers are smaller and its zero sits at a familiar place.
Celsius to Fahrenheit conversion table
The table below covers the readings people look up most often, from hard winter weather to oven heat. Kelvin equivalents are included for the anchor points.
| Celsius (°C) | Fahrenheit (°F) | What it feels like or where it appears |
|---|---|---|
| -40 | -40 | The point where the two scales meet |
| -20 | -4 | A hard frost; home freezer setting |
| -10 | 14 | A cold winter day |
| 0 | 32 | Water freezes (273.15 K) |
| 5 | 41 | Fridge temperature |
| 10 | 50 | A cool spring day |
| 15 | 59 | Mild weather |
| 20 | 68 | Comfortable room temperature |
| 25 | 77 | A warm day (298.15 K) |
| 30 | 86 | A hot summer day |
| 37 | 98.6 | Human body temperature (310.15 K) |
| 40 | 104 | A high fever; a heatwave afternoon |
| 60 | 140 | Hot tap water |
| 80 | 176 | Tea and coffee brewing range |
| 100 | 212 | Water boils (373.15 K) |
| 150 | 302 | A slow oven |
| 180 | 356 | A moderate oven; the classic baking temperature |
| 200 | 392 | A fairly hot oven |
| 220 | 428 | A hot oven for pizza and roasting |
| 250 | 482 | A very hot oven |
A quick mental shortcut for weather temperatures
When you only need a rough idea, such as checking a holiday forecast, double the Celsius figure and add 30. A day of 20 °C becomes 70 °F by this shortcut, close to the exact 68 °F. At 10 °C the shortcut gives 50 °F, which happens to be exact. The trick stays within a couple of degrees across the range of ordinary weather, so it is perfect for deciding whether you need a jacket. It drifts further from the truth as numbers grow, though, so never use it for an oven, a baby bottle or anything medical; use the converter or the full formula there, where a few degrees genuinely matter.
Common temperature conversion mistakes
Forgetting the 32. The most common error is multiplying by 1.8 and stopping there. That turns 20 °C into 36 °F, when the real answer is 68 °F. The offset is not optional; it is half the formula.
Using the offset for temperature differences. A temperature reading and a temperature change are different things. If a room warms by 10 °C, it has warmed by 18 °F, not by 50 °F. For differences, use only the 1.8 factor and skip the 32 entirely.
Putting a degree symbol on kelvin. Kelvin is an absolute unit, like a meter or a kilogram, so it takes no degree sign. Write 310.15 K, not 310.15 °K.
Rounding in the middle. Converting in two steps, such as Fahrenheit to Celsius to kelvin, compounds rounding errors if you round the middle result. Carry the full number through and round once at the end.
Expecting an oven dial to match the exact answer. 180 °C is exactly 356 °F, yet recipes and dials usually say 350 °F or 355 °F. That is rounding by the recipe writer, not an error in your conversion, and the small gap rarely changes the result of a bake.
Frequently asked questions
What is 180 degrees Celsius in Fahrenheit?
180 °C equals 356 °F. Multiply 180 by 1.8 to get 324, then add 32 to get 356. In kelvin, 180 °C is 453.15 K.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 1.8 (or 9/5), then add 32. For example, 25 °C x 1.8 = 45, and 45 + 32 = 77 °F.
How do you convert Kelvin to Celsius?
Subtract 273.15 from the kelvin value. For example, 300 K - 273.15 = 26.85 °C.
At what temperature are Celsius and Fahrenheit equal?
-40. A reading of -40 °C is exactly -40 °F; it is the only point where the two scales agree.
What is normal body temperature in Celsius and Fahrenheit?
Average human body temperature is about 37 °C, which is 98.6 °F (310.15 K). Individual readings vary a little through the day.
Why is Kelvin written without a degree symbol?
Kelvin is an absolute scale that starts at absolute zero, so it is a unit in its own right rather than a degree on a relative scale. Write 300 K, not 300 °K.