Temperature Conversion Matrix

Temperature measures the average kinetic energy of particles in a system, with several scales used worldwide: Celsius (°C) is the global everyday standard; Fahrenheit (°F) is American everyday usage; Kelvin (K) is the SI absolute scale used in science; Rankine (°R) is the absolute version of Fahrenheit used in some American engineering. Unlike other unit categories, temperature scales differ in both their zero points and their degree sizes, so conversion uses formulas — not simple multiplication. The relationship between Celsius and Fahrenheit is °F = (°C × 9/5) + 32, and between Celsius and Kelvin is K = °C + 273.15. Reference points: water freezes at 0°C / 32°F / 273.15 K, water boils at 100°C / 212°F / 373.15 K, absolute zero is −273.15°C / −459.67°F / 0 K. Use temperature conversion for weather forecasts, cooking, medical diagnostics, scientific research, and HVAC engineering.

• ✓Water freezes at 0 °C = 32 °F = 273.15 K. Water boils at 100 °C = 212 °F = 373.15 K at standard pressure.
• ✓Kelvin is the SI unit with zero at absolute zero (coldest possible temperature). Unlike C and F, Kelvin values are never negative.
• ✓The quick mental conversion: °F ≈ 2 × °C + 30. At 20 °C this gives 70 °F (actual: 68 °F — close enough for daily weather).
• ✓Human body core temperature: 37.0 °C = 98.6 °F. Fever starts at 38.0 °C = 100.4 °F.

• ✗Forgetting that temperature conversion is not just multiplication — the offset (273.15 for K, 32 for F) matters.
• ✗Confusing degrees Celsius (°C) with degrees of temperature change. A rise of 5 °C equals a rise of 9 °F.
• ✗Reading a US weather forecast as Celsius — 90 °F is warm (32 °C), not freezing.
• ✗Using Kelvin below zero — absolute zero (0 K) is the minimum, there is no negative Kelvin.