Temperature Converter — Celsius to Fahrenheit & Kelvin

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How to use Temperature Converter

Enter the temperature in the “From” field — for example 350 for an oven at 350 °F.
Pick the scale it is in (Fahrenheit, Celsius, Kelvin, Rankine) in the first dropdown.
Pick the scale you want in the second dropdown — the converted temperature shows instantly.
Use the swap button to reverse direction — handy for checking both ways of a recipe or forecast.

What is Temperature Converter?

A temperature converter translates readings between the Celsius, Fahrenheit, Kelvin and Rankine scales. Unlike length or weight, temperature scales do not share a zero point, so you cannot just multiply by a factor: converting Celsius to Fahrenheit means multiplying by 9/5 and then adding 32, because water freezes at 0 °C but 32 °F.

Kelvin is the scientific scale — same step size as Celsius but starting at absolute zero (−273.15 °C), so water freezes at 273.15 K. Rankine does the same for Fahrenheit (absolute zero = 0 °R, steps the size of °F) and appears mostly in US engineering and thermodynamics work.

About the Temperature Converter

This converter handles all four common scales — Celsius, Fahrenheit, Kelvin and Rankine — applying the exact offset formulas the moment you type a value.

Everyday cases: an American recipe saying 350 °F is 177 °C (or Gas Mark 4 territory); a weather forecast of 30 °C is a hot 86 °F; a fever of 39 °C is 102.2 °F. For science and engineering, it converts lab temperatures to Kelvin (25 °C = 298.15 K) and handles Rankine for thermodynamic calculations. Landmarks worth knowing: −40° is the one point where Celsius and Fahrenheit agree, body temperature is 37 °C / 98.6 °F, and water boils at 100 °C / 212 °F at sea level.

Formulas used: °F = °C × 9/5 + 32, K = °C + 273.15, °R = (°C + 273.15) × 9/5 — computed exactly, in your browser.

Frequently Asked Questions

°F = °C × 9/5 + 32. Example: 25 °C × 9/5 = 45, plus 32 = 77 °F. Going back, °C = (°F − 32) × 5/9.

Double the Celsius and add 30. It gives 30 °C → 90 °F (exact: 86 °F) — within a few degrees for everyday weather ranges.

Kelvin is the SI temperature unit used in science. It starts at absolute zero (−273.15 °C), so it never goes negative: 20 °C room temperature is 293.15 K. Gas laws and physics formulas require Kelvin.

At −40°. Plug it in: −40 × 9/5 + 32 = −72 + 32 = −40. It is the only crossing point of the two scales.

Rankine is Fahrenheit's absolute scale: 0 °R is absolute zero and each degree is the size of 1 °F, so 32 °F = 491.67 °R. It appears mainly in US thermodynamics and aerospace engineering.

Learn more

Celsius to Fahrenheit: The Formula and Quick Conversions

Confused by weather or oven temperatures in the other scale? Here is the Celsius–Fahrenheit formula and a fast mental trick.

Read the guide