How do you convert centigrade to fahrenheit

To convert Celsius to Fahrenheit, start by multiplying the Celsius temperature by 1.8. Then, add 32 to the product to get the degrees in Fahrenheit. For example, if you were trying to convert 20 degrees Celsius to Fahrenheit, first you'd multiply 20 by 1.8 to get 36. Then, you'd add 32 to 36 and get 68. Therefore, 20 degrees Celsius is equal to 68 degrees Fahrenheit. To learn how to convert Fahrenheit to Celsius, scroll down!

Did this summary help you?YesNo

Thanks to all authors for creating a page that has been read 141,316 times.

Conversion of Temperature

Quick Celsius (°C) / Fahrenheit (°F) Conversion:

measure/images/thermometer.js?mode=boxes

Type a value in either box

Or use the slider

Or the Interactive Thermometer

Or this method:

°C to °FDivide by 5, then multiply by 9, then add 32°F to °CDeduct 32, then multiply by 5, then divide by 9

(Explanation Below ...)

Typical Temperatures

(only bold are exactly the same)

 °C°FDescription 220430Hot Oven 180360Moderate Oven 100212Water boils 40104Hot Bath 3798.6Body temperature 3086Beach weather 2170Room temperature 1050Cool Day 032Freezing point of water −180Very Cold Day −40−40Extremely Cold Day
(and the same number!)

Some Tricks:

Daily Temperatures: these three conversions "flip the digits" (accurate within 1°):

°C   °F
28 ⇄ 82
16 ⇄ 61
04 ⇄ 40

Oven Temperatures: in the range 150 to 200 °C we can double °C to get °F (accurate within 8°F):

°C°F
Estimate°F
Actual200400392180360356160320320150300302

Going the other way: for the range 300 to 400 °F we can halve °F to get °C (accurate within 4°C).

Explanation

There are two main temperature scales:

• °C, the Celsius Scale (part of the Metric System, used in most countries)
• °F, the Fahrenheit Scale (used in the US)

They both measure the same thing (temperature!), but use different numbers:

• Boiling water (at normal pressure) measures 100° in Celsius, but 212° in Fahrenheit
• And as water freezes it measures 0° in Celsius, but 32° in Fahrenheit

Like this:

Looking at the diagram, notice:

• The scales start at a different number (0 vs 32), so we will need to add or subtract 32
• The scales rise at a different rate (100 vs 180), so we will also need to multiply

And so, to convert:

from Celsius to Fahrenheit: first multiply by 180100, then add 32

from Fahrenheit to Celsius: first subtract 32, then multiply by 100180

180100 can be simplified to 95, and 100180 can be simplified to 59, so we get this:

°C to °F:   Divide by 5, then multiply by 9, then add 32

°F to °C:   Subtract 32, then multiply by 5, then divide by 9

Example: Convert 25° Celsius (a nice warm day) to Fahrenheit

First: 25° / 5 = 5
Then: 5 × 9 = 45
Then: 45 + 32 = 77° F

Example: Convert 98.6° Fahrenheit (normal body temperature) to Celsius

First: 98.6° − 32 = 66.6
Then: 66.6 × 5 = 333
Then: 333 / 9 = 37° C

We can swap the order of divide and multiply if we want, but don't change the add or subtract. So this is also OK:

Example: Convert 98.6° Fahrenheit to Celsius (again)

First: 98.6° − 32 = 66.6
Then: 66.6 / 9 = 7.4
Then: 7.4 × 5 = 37° C

(Same answer as before, was it easier or harder this way?)

Celsius to Fahrenheit:   (°C × 95) + 32 = °F
Fahrenheit to Celsius:   (°F − 32) × 59 = °C

Other Methods That Work

Use 1.8 instead of 9/5

9/5 is equal to 1.8, so we can also use this method:

Celsius to Fahrenheit:   °C × 1.8 + 32 = °F
Fahrenheit to Celsius:   (°F − 32) / 1.8 = °C

To make "×1.8" easier we can multiply by 2 and subtract 10%, but it only works for °C to °F:

Celsius to Fahrenheit:   (°C × 2) less 10% + 32 = °F

Example: Convert 20° Celsius (A nice day) to Fahrenheit

• 20x2 = 40
• less 10% is 40−4 = 36
• 36+32 = 68° F

Add 40, Multiply, Subtract 40

Since both scales cross at −40° (−40° C equals −40° F) we can:

• add 40,
• multiply by 5/9 (for °F to °C), or 9/5 (for °C to °F)
• subtract 40

Like this:

Celsius to Fahrenheit:   Add 40, multiply by 9/5, then subtract 40
Fahrenheit to Celsius:   Add 40, multiply by 5/9, then subtract 40

Example: Convert 10° Celsius (A cool day) to Fahrenheit

• 10+40 = 50
• 50×9/5 = 90
• 90−40 = 50° F

Quick, but Not Accurate

Celsius to Fahrenheit:   Double, then add 30
Fahrenheit to Celsius:   Subtract 30, then halve

Examples °C → °F:

• 0° C → 0+30 → 30° F (low by 2°)
• 10° C → 20+30 → 50° F (exact!)
• 30° C → 60+30 → 90° F (high by 4°)
• 180° C → 360+30 → 390° F (high by 34°, not good)

Examples °F → °C:

• 40° F → 10/2 → 5° C (almost right)
• 80° F → 50/2 → 25° C (low by about 2°)
• 120° F → 90/2 → 45° C (low by about 4°)
• 450° F → 420/2 → 210° C (low by about 22°, not good)

Footnote: Temperature is a measure of how fast an object's particles are moving.

1041, 1042, 1043, 1044, 3724, 3725, 3726, 3727, 3728, 3729

Interactive Thermometer Metric - Imperial Conversion Charts How to Convert Imperial to Metric How to Convert Metric to Imperial Unit Converter Measurement Index

What is the fastest way to convert Celsius to Fahrenheit?

What does 37.7 Celsius mean in Fahrenheit?

What is 37.0 in Celsius in Fahrenheit?