Temperature Converter

Convert Celsius, Fahrenheit and Kelvin readings with correct offsets, absolute-zero validation and practical temperature examples.

Convert your value

Runs in your browser

Value to convert

Use a decimal point, without commas. Scientific notation such as 1e6 is accepted.

From unit

To unit

Swap exchanges the units and keeps your entered value.

Decimal places

Converted value

Fahrenheit (°F)

Displayed to 6 decimal places. Display rounding does not change the calculation.

Conversion formula

°F = (°C × 9/5) + 32

Scale and offset are applied to the temperature reading. Values below absolute zero are not allowed.

How to use Temperature Converter

Translate weather readings, oven settings and scientific temperatures between Celsius, Fahrenheit and Kelvin. These are absolute temperature readings, not temperature differences: the zero points differ, so an offset is needed as well as a scale factor.

Enter a value, then choose the source and destination units. The result updates as you type.
Use Swap to exchange the units while keeping your input unchanged. Use ± to change the input sign.
Choose 0–10 decimal places for display. Copy result copies the displayed number and its unit.

How the conversion works

Celsius and Kelvin have equal-sized steps, separated by 273.15. Fahrenheit has 9 steps for every 5 Celsius steps and places 0 °C at 32 °F. The selected formula below applies the correct scale and offset in either direction.

°F = (°C × 9/5) + 32
K = °C + 273.15
°C = (°F − 32) × 5/9
K = (°F + 459.67) × 5/9
°C = K − 273.15
°F = (K × 9/5) − 459.67

Absolute zero is −273.15 °C, −459.67 °F or 0 K. Values below the corresponding limit are rejected, including same-unit conversions.
For temperature intervals the offsets do not apply. This tool converts readings, not intervals.

Calculations use browser number precision (about 15–16 significant digits). Extremely large or small results use scientific notation; values outside the numeric range show an error.

Reference: NIST unit conversion factors and temperature formulas. Squared and cubed units are derived from the international inch and foot; the acre uses 43,560 international square feet.

Practical examples

A 20 °C room

Input: 20 °C
Result: 68.0 °F

Multiply 20 by 9/5 and add 32 to obtain 68 °F.

A 350 °F oven setting

Input: 350 °F
Result: 176.67 °C

Subtract 32, then multiply by 5/9. The result rounds to 176.67 °C.

The Kelvin zero point

Input: 0 K
Result: -273.15 °C

Zero kelvin is absolute zero, corresponding to −273.15 °C.

Frequently asked questions

Why does converting 0 °C to Fahrenheit not equal 0 °F?

Temperature scales have different baseline zero points in addition to different degree sizes. On the Celsius scale, 0 °C marks the freezing point of pure water, which corresponds to 32 °F on the Fahrenheit scale. The exact conversion formula is °F = (°C × 9/5) + 32.

What is the lowest temperature this calculator accepts?

The calculator enforces absolute zero as a strict physical boundary: −273.15 °C, −459.67 °F, or 0 K. Any temperature value entered below absolute zero is physically impossible and produces a clear validation message.

Can I use this tool to convert a temperature increase or interval?

This converter calculates specific temperature readings, not temperature differences. For a temperature change (delta), an increase of 1 °C equals an increase of 1.8 °F without adding the 32-degree zero-point offset.