Temperature Converter

About the Temperature Converter

Convert temperatures between Fahrenheit, Celsius, and Kelvin with one converter. Enter a value in any scale and review all three equivalents together.

Temperature conversion is needed constantly: interpreting weather forecasts from other countries, setting oven temperatures from international recipes, understanding scientific data, and working with engineering specifications that use different scales.

The three scales serve different purposes. Fahrenheit is used for weather and cooking in the US. Celsius is the international standard for everyday temperature and most science. Kelvin is the SI unit used in physics, chemistry, and engineering where absolute zero matters.

When This Page Helps

Weather, cooking, science, and medicine all use different temperature scales. This converter shows the matching values and formulas so it is easier to move between everyday and scientific temperature references.

How to Use the Inputs

1. Select the scale you are converting from.
2. Enter the temperature value.
3. All three scale equivalents appear in the result panel.
4. Use the reference points table for quick verification.
5. The formulas used are displayed for learning purposes.

Example Calculation

Tips & Best Practices

• Key reference points: 0°C = 32°F (water freezes), 100°C = 212°F (water boils), 37°C = 98.6°F (body temp).
• −40° is the same in both Fahrenheit and Celsius — the only point where they meet.
• Quick F→C estimate: subtract 30, then halve (gives rough answer for everyday temps).
• Kelvin has no negative values — 0 K is absolute zero (−273.15°C).
• Oven temperatures: 350°F = 177°C, 400°F = 204°C, 450°F = 232°C.

The Three Temperature Scales

Daniel Fahrenheit created his scale using brine (salt water) as 0° and body temperature as roughly 96° (later adjusted). Anders Celsius proposed his centigrade scale with the freezing and boiling points of water as anchors, and Lord Kelvin introduced the absolute scale for thermodynamics.

Practical Temperature Reference Points

Water freezes at 32°F/0°C, room temperature is about 72°F/22°C, body temperature is 98.6°F/37°C, water boils at 212°F/100°C. For cooking: 350°F = 177°C (moderate oven), 450°F = 232°C (hot oven).

Temperature in Science

Kelvin is the SI unit for thermodynamic temperature. Many physics equations require Kelvin because they involve ratios or differences relative to absolute zero. The modern Kelvin definition is tied to the Boltzmann constant rather than a physical reference material.

Frequently Asked Questions

• How do I convert Fahrenheit to Celsius?

  Subtract 32 from the Fahrenheit value, then multiply by 5/9 (or divide by 1.8). For example: 72°F → (72 − 32) × 5/9 = 22.2°C. This formula works for any temperature value.

• What is the difference between Celsius and Kelvin?

  Celsius and Kelvin have the same degree size (1°C = 1 K), but different zero points. 0°C = 273.15 K. Kelvin starts at absolute zero (the coldest possible temperature), while Celsius uses water's freezing point as zero.

• What is absolute zero?

  Absolute zero is 0 Kelvin = −273.15°C = −459.67°F. It is the theoretical lowest possible temperature where all molecular motion ceases. It has been approached in labs but never reached.

• Why does the US use Fahrenheit?

  The Fahrenheit scale was widely adopted in English-speaking countries before Celsius became the scientific and international standard. The US never switched, partly due to the cost and disruption of changing thermometers, weather systems, and public familiarity.

• What temperature is room temperature?

  Room temperature is typically 68–72°F (20–22°C / 293–295 K). In science, "standard temperature" is defined as 25°C (77°F / 298.15 K) or sometimes 20°C depending on the standard used.

• At what temperature are Fahrenheit and Celsius equal?

  Fahrenheit and Celsius read the same value at −40°. This is the unique intersection point: −40°F = −40°C. You can verify: (−40 − 32) × 5/9 = −72 × 5/9 = −40.