Fahrenheit and Celsius are Equal at -40 Degrees


Minus 40 degrees Celsius is exactly minus 40 degrees Fahrenheit. This is the only temperature for which the readings on both scales are equal.

To convert from Celsius to Fahrenheit

C to F -> formula is °C  x  9/5 + 32 = °F
                            -40 * (9/5) + 32 = (-72) + 32 = -40

To convert from Fahrenheit to Celsius

F to C -> formula is (°F  -  32)  x  5/9 = °C
                              (-40 - 32) * (5/9) = (-72) * .55555... = -40

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