Conversion of Temperature

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

measure out/images/thermometer.js?mode=boxes

Type a value in either box

Or use the slider

Or the Interactive Thermometer

Or this method:

°C to °F Carve up by five, and then multiply by nine, then add together 32
°F to °C Deduct 32, then multiply by 5, then split by 9

(Explanation Beneath ...)

Typical Temperatures

(only bold are exactly the aforementioned)

°C °F Description
220 430 Hot Oven
180 360 Moderate Oven
100 212 H2o boils
40 104 Hot Bath
37 98.half-dozen Body temperature
30 86 Beach weather
21 seventy Room temperature
x fifty Cool Day
0 32 Freezing betoken of water
−18 0 Very Common cold 24-hour interval
−40 −40 Extremely Cold Day
(and the aforementioned number!)

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Some Tricks:

Daily Temperatures: these 3 conversions "flip the digits" (accurate within 1°):

°C   °F
28 ⇄ 82
sixteen ⇄ 61
04 ⇄ forty

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

°C °F
Estimate		 °F
Actual
200 400 392
180 360 356
160 320 320
150 300 302

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

Explanation

In that location are two main temperature scales:

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

They both mensurate the aforementioned thing (temperature!), but use different numbers:

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

Like this:

temperature freeze (0 vs 32) and boil (100 vs 212)

Looking at the diagram, notice:

  • The scales first at a unlike number (0 vs 32), so we will demand to add or decrease 32
  • The scales rising at a different rate (100 vs 180), so we will also demand to multiply

And then, to convert:

from Celsius to Fahrenheit: commencement multiply past 180 100 , then add 32

from Fahrenheit to Celsius: first subtract 32, and then multiply past 100 180

180 100 can exist simplified to 9 5 , and 100 180 tin can be simplified to five nine , so we get this:

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

°F to °C: Decrease 32, then multiply by five, then split by nine


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

Kickoff: 25° / 5 = v
And so: 5 × ix = 45
And then: 45 + 32 = 77° F

Case: Convert 98.half dozen° Fahrenheit (normal body temperature) to Celsius

First: 98.half-dozen° − 32 = 66.6
Then: 66.vi × 5 = 333
Then: 333 / nine = 37° C

We can swap the club of split and multiply if nosotros want, just don't change the add or subtract. And then this is also OK:

Example: Convert 98.6° Fahrenheit to Celsius (once more)

First: 98.six° − 32 = 66.6
Then: 66.vi / 9 = 7.4
Then: 7.4 × 5 = 37° C

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

We can write them as formulas:

Celsius to Fahrenheit:   (°C × 9 v ) + 32 = °F
Fahrenheit to Celsius:   (°F − 32) × v ix = °C

Other Methods That Work

Use one.8 instead of 9/5

ix/5 is equal to 1.8, so we can as well use this method:

Celsius to Fahrenheit:   °C × 1.8 + 32 = °F
Fahrenheit to Celsius:   (°F − 32) / ane.8 = °C

To brand "×1.8" easier we can multiply past ii and subtract 10%, only information technology only works for °C to °F:

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

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

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

Add 40, Multiply, Decrease twoscore

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

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

Like this:

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

Example: Catechumen 10° Celsius (A cool twenty-four hours) to Fahrenheit

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

Quick, but Not Accurate

Celsius to Fahrenheit:   Double, then add together xxx
Fahrenheit to Celsius:   Subtract thirty, so halve

Examples °C → °F:

  • 0° C → 0+30 → 30° F (low by 2°)
  • ten° C → 20+30 → fifty° F (verbal!)
  • 30° C → 60+30 → 90° F (high by iv°)
  • 180° C → 360+30 → 390° F (loftier by 34°, not good)

Examples °F → °C:

  • 40° F → x/2 → 5° C (almost right)
  • fourscore° F → 50/2 → 25° C (low by about two°)
  • 120° F → 90/2 → 45° C (depression by about 4°)
  • 450° F → 420/ii → 210° C (low by well-nigh 22°, not adept)

temperature particles

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

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