Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin, and Rankine with formulas and instant results.

Value
From
To
°F = (°C × 9/5) + 32
Temperature Reference Points
Description°C°FK
Water boiling point 100 212 373.15
Body temperature 37 98.6 310.15
Room temperature 20–22 68–72 293–295
Water freezing point 0 32 273.15
Absolute zero −273.15 −459.67 0

Frequently Asked Questions

Use the formula: °F = (°C × 9/5) + 32. For example, 100°C = (100 × 1.8) + 32 = 212°F. The reverse is: °C = (°F − 32) × 5/9.
Absolute zero is the lowest theoretically possible temperature — 0 Kelvin = −273.15°C = −459.67°F. At absolute zero, particles have the minimum possible kinetic energy. It has been approached but never fully achieved in a laboratory.
Kelvin is the SI base unit of temperature. It starts at absolute zero and uses the same scale increment as Celsius. Convert: K = °C + 273.15. Kelvin is used in science, engineering, and astrophysics because it is an absolute (thermodynamic) scale with no negative values.
Rankine is an absolute temperature scale that uses Fahrenheit-sized degrees. °R = °F + 459.67. Absolute zero is 0°R. It is used in some engineering fields in the United States, particularly in thermodynamics calculations that require an absolute scale but use Fahrenheit units.
To convert Fahrenheit to Celsius, use °C = (°F − 32) × 5/9. For example, 98.6°F = (98.6 − 32) × 5/9 = 37°C. A quick mental trick: subtract 30 and halve the result for a rough estimate (e.g., 70°F → (70−30)/2 = 20°C; exact: 21.1°C).
Kelvin appears in everyday products more than most people realize. Light bulb color temperature is measured in Kelvin (2700K = warm white, 6500K = daylight). Camera white balance settings use Kelvin. Kelvin is also standard in scientific research, astrophysics, and cryogenics.
The classic normal body temperature is 98.6°F (37°C), but research shows the average is closer to 97.9°F (36.6°C) and varies by individual, time of day, and measurement method. A fever is generally considered to be 100.4°F (38°C) or higher.
The US adopted Fahrenheit in the 18th century before the metric system was established. Political resistance and the high cost of conversion have kept it in place. The Fahrenheit scale was designed so that human body temperature is near 100°F and salt water freezes at 0°F, but these benchmarks are not exact.
Common oven conversions: 325°F = 163°C (slow/low), 350°F = 177°C (moderate, most cakes), 375°F = 191°C, 400°F = 204°C (roasting), 425°F = 218°C, 450°F = 232°C (high heat, pizza). Gas marks are also used in UK recipes (Gas Mark 4 ≈ 350°F / 177°C).
Fahrenheit and Celsius are equal at −40° (both scales read −40 at this point). This is because the two scales converge when solving °C = °F in the conversion formula: (°F − 32) × 5/9 = °F gives °F = −40. This temperature occurs in extreme Arctic and Antarctic conditions.

About This Temperature Converter

This free temperature converter converts between Celsius, Fahrenheit, Kelvin, and Rankine using exact formulas. Enter a temperature in any scale and the result updates instantly along with the conversion formula used.

When to use this converter

  • Converting weather temperatures between °C and °F when traveling internationally
  • Scientific and laboratory calculations requiring Kelvin
  • Understanding oven and cooking temperatures across different countries
  • Engineering and thermodynamics work involving the Rankine scale

Standards & References

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