AboutProjectsToolsNotesUses

Temperature Converter

Convert temperatures between Celsius, Fahrenheit, Kelvin and Rankine.

Enter a temperature in any scale and see its equivalent in the others, with the conversion formula displayed so you can verify it by hand. Handles negative values and very large/small inputs without rounding artefacts.

Common use cases: cooking and baking when a recipe uses the other scale, weather forecasts on travel, scientific calculations that demand Kelvin, and double-checking the result of a quick mental conversion.

Frequently asked questions

What's the formula behind C ↔ F?
F = C × 9/5 + 32 and C = (F − 32) × 5/9. The two scales coincide at -40 (same number on both). 0°C is the freezing point of water at sea level; 100°C is its boiling point. 32°F and 212°F are the same two reference points.
Why are there three scales at all?
Historical accident. Fahrenheit was first (1724), based on a brine mixture and human body temperature. Celsius (1742) anchored on water's phase changes. Kelvin (1848) anchored on absolute zero, the temperature at which molecular motion stops, making it the only scale where temperature ratios are physically meaningful.
When should I use Kelvin?
For any physical or chemical calculation involving the gas laws, blackbody radiation, or thermodynamics, anywhere a temperature ratio matters. 2 × 273 K = 546 K is meaningful (twice as hot in an absolute sense); 2 × 0°C = 0°C is meaningless.
What about Rankine?
Rankine is to Fahrenheit what Kelvin is to Celsius, anchored at absolute zero, same step size as Fahrenheit. Used in some US engineering disciplines (jet engines, HVAC). Rarely seen outside those domains.

Other Converters

View all tools →

Image to Base64

Convert images to Base64 encoded strings

IMG

Roman Numeral Converter

Convert between numbers and Roman numerals

Ⅻ

Base Converter

Convert numbers between different bases (binary, octal, hex, etc.)

∑

Color Converter

Convert colors between HEX, RGB, HSL, and more formats

◆

JSON to TypeScript

Convert JSON to TypeScript type definitions

{}

JSON to Rust

Convert JSON to Rust struct definitions

{}

CSS Unit Converter

Convert between CSS units (px, em, rem, %, pt)

CSS

Text Case Converter

Convert text between different cases (camelCase, snake_case, etc.)

Aa

Unix Time Converter

Convert between Unix timestamps and readable dates

time

Timezone Converter

Convert times between timezones worldwide for meetings and global coordination

◆

JSON to CSV

Convert JSON arrays to CSV format for spreadsheets and data export

⇄

CSV to JSON

Convert CSV data to JSON format for APIs and applications

⇄