Celsius to Fahrenheit Converter
Convert °C to °F instantly, with the exact formula and charts
°F = °C × 9/5 + 32. Multiply the Celsius temperature by 1.8, then add 32. For example, 20 °C = 68 °F, 37 °C = 98.6 °F and 100 °C = 212 °F.
How to convert Celsius to Fahrenheit
Both scales were built around water. Celsius puts freezing at 0 and boiling at 100, a gap of 100 degrees. Fahrenheit puts the same two points at 32 and 212, a gap of 180 degrees. So each Celsius degree is 180/100 = 1.8 Fahrenheit degrees, and the Fahrenheit scale starts 32 degrees higher. That gives the two steps of the formula: scale by 1.8, then shift by 32. To run the steps backwards, use the Fahrenheit to Celsius converter; for Rankine, Réaumur and every other scale, open the temperature converter.
The order matters. Multiply first and add 32 second: 25 °C × 1.8 = 45, and 45 + 32 = 77 °F. Adding first gives (25 + 32) × 1.8 = 102.6, which is wrong. The other trap is a temperature change. A rise of 10 °C is a rise of 18 °F, with no 32 added, because the offset cancels out when you subtract two readings. Physics and chemistry usually want kelvin, which the Celsius to kelvin converter gives by adding 273.15.
Step by step
- Take the temperature in degrees Celsius.
- Multiply it by 1.8 (the same as 9/5).
- Add 32 to the result.
- Round: whole degrees for weather and ovens, one decimal for body temperature.
See it on a scale
Worked examples
A comfortable 20 °C room, a normal body temperature of 37 °C, and the 180 °C oven setting found in countless recipes.
°F = 20 × 9/5 + 32 = 68
= 68 °F
°F = 37 × 9/5 + 32 = 98.6
= 98.6 °F
°F = 180 × 9/5 + 32 = 356
= 356 °F
What is 1 degree Celsius in Fahrenheit?
1 °C is 33.8 °F as a temperature reading, but a change of 1 °C is a change of exactly 1.8 °F, because the 32-degree offset only applies to readings.
The reading comes straight from the formula: 1 × 1.8 + 32 = 33.8 °F, just above freezing. A change works differently. When a room warms from 20 °C to 21 °C, it goes from 68 °F to 69.8 °F, a rise of 1.8 °F, because both readings carry the same 32 and it cancels when you subtract one from the other.
| Celsius value | As a reading | As a change |
|---|---|---|
| 1 °C | 33.8 °F | 1.8 °F |
| 2 °C | 35.6 °F | 3.6 °F |
| 5 °C | 41 °F | 9 °F |
| 10 °C | 50 °F | 18 °F |
| 20 °C | 68 °F | 36 °F |
This matters for climate figures. The 1.5 °C warming limit named in the 2015 Paris Agreement is a warming of 2.7 °F, not 34.7 °F. Thermostat swings, oven tolerances and fever rises follow the same rule: multiply the change by 1.8 and leave the 32 out.
How do I convert Celsius to Fahrenheit in Excel or Google Sheets?
Type =A2*9/5+32 in the cell next to a Celsius value in A2, or use the built-in =CONVERT(A2,"C","F"), which works the same way in both Excel and Google Sheets.
Both formulas return 68 for 20 and 212 for 100. Copy the cell down beside the rest of your readings and each row converts on its own. To tidy the output, wrap it in ROUND: =ROUND(A2*9/5+32,1) keeps one decimal, which suits body temperatures, and =ROUND(A2*9/5+32,0) gives whole degrees for weather.
- Fahrenheit back to Celsius: =(A2-32)*5/9, or =CONVERT(A2,"F","C").
- A temperature change, not a reading: =A2*9/5 with no 32, so a 12 °C daily swing returns 21.6 °F.
- Missing parentheses in the reverse formula: =A2-32*5/9 is wrong, because the spreadsheet multiplies first and subtracts only 17.78.
Excel also accepts the longer unit codes "cel" and "fah", which are handy if a colleague's workbook already uses them.
Celsius to Fahrenheit conversion chart
Common Celsius temperatures converted to Fahrenheit, from deep winter to a hot oven. Because 1 °C is exactly 1.8 °F, every whole-degree Celsius value converts to at most one decimal place.
| Celsius (°C) | Fahrenheit (°F) |
|---|---|
| -40 °C | -40 °F |
| -30 °C | -22 °F |
| -25 °C | -13 °F |
| -20 °C | -4 °F |
| -15 °C | 5 °F |
| -10 °C | 14 °F |
| -5 °C | 23 °F |
| 0 °C | 32 °F |
| 5 °C | 41 °F |
| 10 °C | 50 °F |
| 15 °C | 59 °F |
| 16 °C | 60.8 °F |
| 18 °C | 64.4 °F |
| 20 °C | 68 °F |
| 21 °C | 69.8 °F |
| 22 °C | 71.6 °F |
| 24 °C | 75.2 °F |
| 25 °C | 77 °F |
| 26 °C | 78.8 °F |
| 28 °C | 82.4 °F |
| 30 °C | 86 °F |
| 32 °C | 89.6 °F |
| 35 °C | 95 °F |
| 37 °C | 98.6 °F |
| 38 °C | 100.4 °F |
| 40 °C | 104 °F |
| 45 °C | 113 °F |
| 50 °C | 122 °F |
| 60 °C | 140 °F |
| 70 °C | 158 °F |
| 80 °C | 176 °F |
| 90 °C | 194 °F |
| 100 °C | 212 °F |
| 150 °C | 302 °F |
| 180 °C | 356 °F |
| 200 °C | 392 °F |
| 220 °C | 428 °F |
| 250 °C | 482 °F |
Celsius vs Fahrenheit: what is the difference?
Both scales measure how hot or cold something is, but they disagree on the size of a degree and on where zero sits. The first rows come from the exact definitions; the rest show how each scale is used.
| Attribute | Celsius | Fahrenheit |
|---|---|---|
| Symbol | °C | °F |
| System | Metric (SI derived) | US customary |
| Defined as | K − 273.15 | °C × 9/5 + 32 |
| Water freezes at | 0 °C | 32 °F |
| Water boils at (1 atm) | 100 °C | 212 °F |
| Absolute zero | -273.15 °C | -459.67 °F |
| Size of one degree | Exactly 1 K | 5/9 K, about 0.5556 K |
| Degrees from freezing to boiling water | 100 | 180 |
| SI status | SI derived unit with a special name | Not an SI unit; its exact conversion appears in NIST SP 811, Appendix B |
| Normal body temperature | 37 °C | 98.6 °F |
| Where it is used | Weather, cooking and medicine in nearly every country, and all scientific work | Everyday weather, cooking and home thermometers in the United States and a few other places |
5 key differences
- A change of 10 °C is exactly a change of 18 °F, because one Celsius degree spans 1.8 Fahrenheit degrees.
- The Celsius scale fits 100 degrees between water's freezing and boiling points at standard pressure, and the Fahrenheit scale fits 180.
- Celsius and Fahrenheit share exactly one reading, −40, where the two scales cross.
- The degree Celsius belongs to the SI, whereas the degree Fahrenheit sits outside it and is converted through the Celsius or kelvin scales.
- A comfortable 20 °C room reads 68 °F, so everyday Fahrenheit numbers are usually the larger of the two.
Weather temperatures in Celsius and Fahrenheit
Forecasts outside the United States are given in Celsius. This chart turns them into the Fahrenheit numbers US readers know, with a rough sense of how each one feels. Wind speeds in those forecasts are converted by the km/h to mph converter.
| Celsius | Fahrenheit | What it feels like |
|---|---|---|
| −30 °C | −22 °F | Dangerous cold; frostbite risk within minutes in wind |
| −20 °C | −4 °F | Severe winter cold |
| −10 °C | 14 °F | Hard frost, very cold day |
| −5 °C | 23 °F | Freezing winter day |
| 0 °C | 32 °F | Water freezes; ice on roads |
| 5 °C | 41 °F | Cold; winter coat weather |
| 10 °C | 50 °F | Cool; light jacket |
| 15 °C | 59 °F | Mild spring or autumn day |
| 20 °C | 68 °F | Comfortable room temperature |
| 25 °C | 77 °F | Warm summer day |
| 30 °C | 86 °F | Hot |
| 35 °C | 95 °F | Very hot; heat advisories are common |
| 40 °C | 104 °F | Extreme heat |
| 45 °C | 113 °F | Record-level heat in most places |
Oven temperatures: Celsius to Fahrenheit
Recipes from the UK, Europe and Australia give oven heat in Celsius. The exact conversion rarely lands on a US dial setting, so the third column rounds to the nearest 25 °F. For a fan (convection) oven, recipes usually say to set about 20 °C lower. Ingredient amounts convert with the cups to grams converter.
| Celsius | Fahrenheit (exact) | Nearest US dial | Typical use |
|---|---|---|---|
| 100 °C | 212 °F | 200 °F | Water boils at sea level; drying meringues |
| 120 °C | 248 °F | 250 °F | Very slow oven, slow roasting |
| 140 °C | 284 °F | 275 °F | Slow cooking, braising |
| 150 °C | 302 °F | 300 °F | Low oven; cheesecakes, custards |
| 160 °C | 320 °F | 325 °F | Moderately low; fruit cakes |
| 170 °C | 338 °F | 350 °F | Moderate; many cakes |
| 180 °C | 356 °F | 350 °F | The standard “moderate oven”; cakes, cookies, casseroles |
| 190 °C | 374 °F | 375 °F | Moderately hot; muffins, pastry |
| 200 °C | 392 °F | 400 °F | Hot; roast vegetables, bread |
| 220 °C | 428 °F | 425 °F | Hot; pizza, roast potatoes |
| 230 °C | 446 °F | 450 °F | Very hot; bread with steam |
| 250 °C | 482 °F | 475 °F | Maximum on many home ovens |
Body temperature chart: °C to °F
Thermometers outside the US read in Celsius, and a tenth of a degree matters here, so values are shown to one decimal. Normal temperature varies from person to person, by time of day and by where it is measured. This chart is general information, not medical advice: if you are worried about a fever, especially in a baby, contact a doctor.
| Celsius | Fahrenheit | What it usually means |
|---|---|---|
| 35.0 °C | 95.0 °F | Below this is hypothermia |
| 35.5 °C | 95.9 °F | Low |
| 36.0 °C | 96.8 °F | Low end of normal |
| 36.5 °C | 97.7 °F | Typical normal |
| 37.0 °C | 98.6 °F | The classic “normal” 98.6 °F |
| 37.5 °C | 99.5 °F | Slightly raised |
| 38.0 °C | 100.4 °F | Fever threshold used by the CDC |
| 38.5 °C | 101.3 °F | Fever |
| 39.0 °C | 102.2 °F | Fever |
| 39.5 °C | 103.1 °F | High fever |
| 40.0 °C | 104.0 °F | High fever; get medical advice |
| 40.5 °C | 104.9 °F | Very high; seek urgent care |
| 41.0 °C | 105.8 °F | Medical emergency |
How do you convert Celsius to Fahrenheit in your head?
Double the Celsius number, take away a tenth of the result, then add 32; that is exact. The popular “double it and add 30” is quicker but only exact at 10 °C.
The most popular mental trick for Celsius to Fahrenheit is double the Celsius and add 30. It works because 2 is close to 1.8 and 30 is close to 32. For 15 °C it gives 60 °F against an exact 59 °F, which is close enough to decide on a jacket.
Where the shortcut goes wrong
The error is easy to work out: (2C + 30) − (1.8C + 32) = 0.2C − 2. That means the shortcut is exact at 10 °C, reads 2 °F too low at 0 °C, 4 °F too high at 30 °C and 6 °F too high at 40 °C. For ovens it breaks down completely: 180 °C becomes 390 °F instead of 356 °F, a 34 °F overshoot that can burn a cake.
An exact version you can do in your head
Double it, subtract 10%, then add 32. Doubling and taking away a tenth is the same as multiplying by 1.8, so the answer is exact. For 25 °C: 25 × 2 = 50, 50 − 5 = 45, and 45 + 32 = 77 °F.
Anchors worth memorizing
- −40 °C = −40 °F, the one point where the scales meet.
- 0 °C = 32 °F (freezing) and 100 °C = 212 °F (boiling at sea level).
- 16 °C ≈ 61 °F and 28 °C ≈ 82 °F: the digits swap (exactly 60.8 °F and 82.4 °F).
- Every 5 °C is 9 °F, so 10 °C = 50 °F, 15 °C = 59 °F, 20 °C = 68 °F, 25 °C = 77 °F and 30 °C = 86 °F.
Shortcut versus exact: the error at each temperature
How far “double it and add 30” drifts from the exact formula. A plus sign means the shortcut reads too warm. The error grows by 1 °F for every 5 °C away from 10 °C.
| Celsius | Exact Fahrenheit | Double it and add 30 | Error |
|---|---|---|---|
| −20 °C | −4 °F | −10 °F | −6 °F |
| −10 °C | 14 °F | 10 °F | −4 °F |
| 0 °C | 32 °F | 30 °F | −2 °F |
| 5 °C | 41 °F | 40 °F | −1 °F |
| 10 °C | 50 °F | 50 °F | 0 °F |
| 15 °C | 59 °F | 60 °F | +1 °F |
| 20 °C | 68 °F | 70 °F | +2 °F |
| 25 °C | 77 °F | 80 °F | +3 °F |
| 30 °C | 86 °F | 90 °F | +4 °F |
| 35 °C | 95 °F | 100 °F | +5 °F |
| 40 °C | 104 °F | 110 °F | +6 °F |
| 100 °C | 212 °F | 230 °F | +18 °F |
| 180 °C | 356 °F | 390 °F | +34 °F |
Sources and further reading
The standards and references behind the numbers on this page. Links open in a new tab.
Standards and official sources
Further reading
- Degree CelsiusWikipedia
- Degree FahrenheitWikipedia
Celsius to Fahrenheit FAQs
Short, exact answers to what people ask most.
What is the formula to convert Celsius to Fahrenheit?
Multiply the Celsius temperature by 9/5 (1.8) and then add 32: °F = °C × 1.8 + 32. For example, 30 °C × 1.8 = 54, and 54 + 32 = 86 °F.
Is “double it and add 30” accurate?
It is exact only at 10 °C and drifts by 1 °F for every 5 °C away from it. It is fine for weather between about 0 and 25 °C, but for ovens it is badly off: 180 °C comes out as 390 °F instead of 356 °F.
What is 37 °C in Fahrenheit?
37 °C is exactly 98.6 °F, the traditional figure for normal human body temperature. Healthy readings commonly range a little above and below it.
What is 180 °C in Fahrenheit for an oven?
180 °C is exactly 356 °F. US ovens are set in 25 °F steps, so use 350 °F, which is the usual American equivalent of a 180 °C moderate oven.
Is 38 °C a fever?
Yes. The US CDC treats a temperature of 38 °C (100.4 °F) or higher as a fever. If you are concerned, especially about an infant, contact a doctor.
At what temperature are Celsius and Fahrenheit the same?
At −40. Because −40 × 1.8 + 32 = −40, the two scales show the same number only at −40 °C, which is −40 °F.
What is 25 °C in Fahrenheit?
25 °C is exactly 77 °F, the feel of a warm summer day. The working is 25 × 1.8 = 45, plus 32.
What is 40 °C in Fahrenheit?
40 °C is exactly 104 °F. As weather it is extreme heat, and as a body temperature it is a high fever that needs medical advice.
What is 100 °C in Fahrenheit?
100 °C is exactly 212 °F, the textbook boiling point of water at sea-level pressure. At higher altitudes water boils at a lower temperature.
What is −10 °C in Fahrenheit?
−10 °C is 14 °F, a hard frost. Fahrenheit readings stay above zero until −17.78 °C, which is 0 °F.
Related conversions
Conversion formula from NIST SP 811 (2008), Appendix B; the degree Celsius per the BIPM SI Brochure (9th ed., 2019); fever threshold of 38 °C (100.4 °F) per the US Centers for Disease Control and Prevention; the 1.5 °C warming limit from the 2015 Paris Agreement; spreadsheet syntax from the Microsoft Excel and Google Sheets CONVERT function documentation. Last updated . How we verify our numbers.