Centigrade vs Fahrenheit cheat sheet: Difference between revisions

Revision as of 17:05, 7 October 2022

Celsius = 5/9 (F - 32)

Fahrenheit = (9/5 C) + 32

Double C and add 32 becomes less accurate as the temperatures rise. It is exactly right at 0 C, off by 8 at 40 C, and off by 20 at 100 C.

The doubling is off by 10%. 2 is 10/5, but the correct formula is 9/5, so the right factor is nine/tenths below the fudge factor.

Double C, subtract roughly 10% of that product from itself, then add 32 improves the result.

@@ Line 10: / Line 10: @@
 |- valign="top"
 |align="right" style="background:#C800FF"| 0°
-| 32°
+|align="center"| 32°
 | rowspan="2"|
 cold
 |- valign="top"
 |align="right" style="background:#C800FF"| 5°
-| 41°
+|align="center"|| 41°
 <!-- merged -->
 |- valign="top"
 |align="right" style="background:#069EEE"| 10°
-| 50°
+|align="center"|| 50°
 | rowspan="2"|
 chilly
 |- valign="top"
 |align="right" style="background:#069EEE"| 15°
-| 59°
+|align="center"|| 59°
 <!-- merged -->
 |- valign="top"
 |align="right" style="background:#B6DAEC"| 20°
-| 68°
+|align="center"|| 68°
 | cool
 |- valign="top"
 |align="right" style="background:#FFEE00"| 25°
-| 77°
+|align="center"|| 77°
 | warm
 |- valign="top"
 |align="right" style="background:#FFDD00"| 30°
-| 86°
+|align="center"|| 86°
 | hot
 |- valign="top"
 |align="right" style="background:#FF6F00"| 35°
-| 95°
+|align="center"|| 95°
 | tropical
 |- valign="top"
 |align="right" style="background:#FF0000"| 40°
-| 104°
+|align="center"|| 104°
 | melting point
 |}
-== (2 Ã— C) + 32 ==
+== (2C° - 0.1(2C°)) + 32 ==
 Double C and add 32 becomes less accurate as the temperatures rise.  It is exactly right at 0 C, off by 8 at 40 C, and off by 20 at 100 C.