Temperature Converter

1. Type in any scale. Enter a temperature in Celsius, Fahrenheit, Kelvin, or Rankine. The other three fields update immediately.
2. Use the quick-reference buttons. Below the fields are preset buttons for common reference points: water freezing (0°C), normal body temperature (37°C), water boiling (100°C), and absolute zero (-273.15°C).
3. Enter negative values for sub-zero temperatures. Type -40 in either the Celsius or Fahrenheit field, which are equal at that point (-40°C = -40°F).
4. Check the warning indicator. If you enter a value below absolute zero, a notice appears. Temperatures below -273.15°C are physically impossible.

Example: an oven preheated to 375°F. Type 375 in the Fahrenheit field to see: 190.556°C, 463.706 K, 834.67°R.

Unlike length or weight, temperature scales have different zero points, so the conversion formulas are not simple multiplications. Celsius is the intermediate used here.

Key fixed points:

• Absolute zero: -273.15°C = -459.67°F = 0 K = 0°R
• Water freezes: 0°C = 32°F = 273.15 K = 491.67°R
• Water boils: 100°C = 212°F = 373.15 K = 671.67°R
• Human body: 37°C = 98.6°F = 310.15 K = 558.27°R
• Equal point: -40°C = -40°F (the only temperature the same on both scales)