Temperature Conversion Chart

Convert between Celsius, Fahrenheit, Kelvin and Rankine at once, with oven gas marks, body temperature reference and a printable chart over any range.


Type a temperature on any scale and all four are worked out at once. A comma works as the decimal point, so 37,5 and 37.5 both do the same thing.
Celsius
20°C
Fahrenheit
68°F
Kelvin
293.15K
Rankine
527.67°R

20 °C is 68 °F, 293.15 K and 527.67 °R.

Common ones:

Printable conversion chart

Temperature conversion chart, -40 to 100 Celsius

Celsius (°C) Fahrenheit (°F) Kelvin (K) Rankine (°R)
-40 -40 233.15 419.67
-35 -31 238.15 428.67
-30 -22 243.15 437.67
-25 -13 248.15 446.67
-20 -4 253.15 455.67
-15 5 258.15 464.67
-10 14 263.15 473.67
-5 23 268.15 482.67
0 32 273.15 491.67
5 41 278.15 500.67
10 50 283.15 509.67
15 59 288.15 518.67
20 68 293.15 527.67
25 77 298.15 536.67
30 86 303.15 545.67
35 95 308.15 554.67
40 104 313.15 563.67
45 113 318.15 572.67
50 122 323.15 581.67
55 131 328.15 590.67
60 140 333.15 599.67
65 149 338.15 608.67
70 158 343.15 617.67
75 167 348.15 626.67
80 176 353.15 635.67
85 185 358.15 644.67
90 194 363.15 653.67
95 203 368.15 662.67
100 212 373.15 671.67

29 rows. Values are rounded to two decimal places.

How the scales relate to each other

Celsius and Fahrenheit are both defined by where water freezes and boils, they just chose different numbers for it: 0 and 100 against 32 and 212. That is 100 Celsius degrees covering the same span as 180 Fahrenheit degrees, which is where the 9/5 in the formula comes from, and the 32 is simply the offset between the two zeros. Kelvin uses degrees the same size as Celsius but starts at absolute zero instead of at the freezing point, so it is only ever an addition of 273.15. Rankine does for Fahrenheit what Kelvin does for Celsius. Every conversion on this page is done by turning the value into Celsius first and then back out again, so the four answers can never disagree with each other.

°F = °C × 9/5 + 32
°C = (°F − 32) × 5/9
K = °C + 273.15
°R = °F + 459.67

Oven temperatures and gas marks

Oven markings are a special case, because they are not exact conversions and were never meant to be. The Fahrenheit column steps in a perfectly regular 25 degrees all the way from gas mark 1 to gas mark 9, while the Celsius column skips 160 and 210 so that its own numbers stay round. The two columns therefore drift apart and back together again: gas mark 1 is printed as 140 °C and 275 °F when 140 °C is really 284 °F, and the widest gap of all is at gas mark 3, labelled 170 °C and 325 °F when 170 °C is actually 338 °F. Thirteen Fahrenheit degrees makes no practical difference to a cake, which is why nobody has ever bothered to reconcile the two columns. The fan column is the same setting for a fan or convection oven, which runs about 20 °C cooler for the same result because the moving air transfers heat more efficiently.

Gas mark Conventional oven (°C) Fan oven (°C) Fahrenheit (°F)
1/4 110 90 225
1/2 120 100 250
1 140 120 275
2 150 130 300
3 170 150 325
4 180 160 350
5 190 170 375
6 200 180 400
7 220 200 425
8 230 210 450
9 240 220 475

Body temperature, and where 98.6 came from

The familiar 98.6 °F is not a measurement, it is a conversion. The German physician Carl Wunderlich published 37 °C as the average in 1868, and translating that to Fahrenheit gives 98.6 exactly, which is how a rounded figure acquired a decimal place it never earned. Larger modern studies put the average closer to 36.6 °C (97.9 °F), and any one person swings by half a degree or so across the day, lowest in the early morning. A reading also depends on where it was taken, with the mouth and armpit running cooler than the ear or rectum. The threshold usually used for a fever is 38 °C (100.4 °F) and hypothermia begins below 35 °C (95 °F), but these are reference figures rather than a diagnosis; anything worrying is a question for a doctor.

Kelvin and Rankine, the absolute scales

Kelvin is the SI unit and is written 295.15 K, with no degree symbol and never as degrees Kelvin, because the unit is the kelvin rather than a degree of anything. It starts at absolute zero, the point at which there is no thermal energy left to remove, so a negative kelvin reading is not a cold temperature but an impossible one. Since 2019 the kelvin has been defined by fixing the value of the Boltzmann constant rather than by the properties of water. Rankine is the same idea applied to Fahrenheit: it starts at absolute zero and counts in Fahrenheit-sized degrees, so it is simply Fahrenheit plus 459.67, and it still turns up in some United States engineering work.

Worth knowing

  • The two everyday scales cross at minus 40, the one temperature that is the same number in Celsius and in Fahrenheit.
  • To convert Celsius to Fahrenheit in your head, double it and add 30. It is out by a couple of degrees but it is close enough for weather.
  • Absolute zero is minus 273.15 °C, minus 459.67 °F and 0 K, and nothing on this page will let you go below it.
  • A difference of 1 °C is a difference of 1.8 °F, so a two degree Celsius rise is nearly four Fahrenheit degrees.
  • The chart prints on its own, without the rest of the page around it, so it can go straight on a fridge or in a recipe folder.

Frequently asked questions

Multiply by 9/5, which is the same as multiplying by 1.8, then add 32. So 20 °C becomes 36 plus 32, which is 68 °F. Going the other way, subtract 32 first and then multiply by 5/9. The order matters: subtracting after dividing gives the wrong answer.

Minus 40. It is the single point where the two scales cross, so minus 40 °C and minus 40 °F are the same temperature. It falls out of the formulas: the only value where x equals 1.8x plus 32 is minus 40.

356 °F exactly. Recipes normally call it 350 °F, because oven dials are marked in round numbers rather than in exact conversions, and six Fahrenheit degrees makes no difference to a bake. The same rounding is why gas mark 4 is labelled both 180 °C and 350 °F.

Because it is 37 °C converted. Carl Wunderlich published 37 °C as the average in 1868, and 37 times 1.8 plus 32 comes to 98.6 exactly, so a rounded Celsius figure turned into a suspiciously precise Fahrenheit one. Modern studies suggest the true average is nearer 36.6 °C, or 97.9 °F.

Just kelvin. The unit is the kelvin, so a temperature is written as 295.15 K with no degree symbol and read as two hundred and ninety five point one five kelvin. Celsius, Fahrenheit and Rankine all keep their degree symbols; kelvin lost its in 1967.

The coldest temperature that can exist, the point at which a system has given up all the thermal energy it can. It is 0 K, minus 273.15 °C and minus 459.67 °F. It cannot actually be reached, only approached, and this page will refuse any value below it.

About 20 °C lower for the same result. A fan moves hot air around the oven so heat reaches the food faster, which means 180 °C in a conventional oven is roughly 160 °C with the fan on. The gas mark and the Fahrenheit marking on the chart refer to the conventional setting.

Yes. Set the range, the step and the scale you want, then press Print the chart and everything else on the page is hidden, so the table comes out on its own with no menus or headings around it. Ranges of up to 150 rows are allowed.

How do you convert between temperature scales?

Multiply Celsius by 9/5 and add 32 for Fahrenheit, or add 273.15 for kelvin. Type any temperature above and all four scales are worked out at once, or build a printable chart over any range you like. Water freezes at 0 °C and 32 °F, boils at 100 °C and 212 °F, and the two scales meet at minus 40.