Convert a reading or a temperature change
- Choose reading or change, then enter a value and its source scale.
- Select the target scale and convert.
- Review the reading and absolute temperature, then copy or download.
Offset formulas and examples
0 °C = 32 °F = 273.15 K = 491.67 °R. 100 °C = 212 °F, and −40 °C = −40 °F. Celsius and Fahrenheit have different zero points, so a temperature reading cannot be converted by a multiplier alone.
| Source scale | Kelvin formula | Minimum input |
|---|---|---|
| Celsius | T = x + 273.15 | −273.15 °C |
| Fahrenheit | T = (x + 459.67) × 5/9 | −459.67 °F |
| Kelvin | T = x | 0 K |
| Rankine | T = x × 5/9 | 0 °R |
Target conversion reverses its scale’s formula. Direct Celsius/Fahrenheit formulas are °F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9. Definitions follow NIST’s temperature guide and temperature conversion factors.
Limits and privacy
Reading mode converts ordinary temperatures at or above absolute zero, with a maximum entered value of 10⁹ in the selected scale. Below-bound inputs are rejected rather than clipped. This is a scale conversion, not a thermometer calibration, heat-energy calculation or specialized negative-temperature model.
Display uses up to 12 significant digits and six decimal places or scientific notation for extremes. CSV retains the numeric floating-point calculation and can show small rounding effects. Values stay in browser memory without uploads or saved temperatures. Reset clears the result and restores 0 °C to °F. Live conversion waits 300 ms. Swap preserves the entered number; result reuse preserves the numeric result and reverses the scales. These actions, examples and Reset offer one Undo step. Typing discards action history. Temperature changes allow signed values from −10⁹ to 10⁹ and do not have an absolute-zero limit. Every-scale CSV includes all four supported scales and identifies reading or change mode.
Can I convert a temperature increase with these formulas?
Choose Temperature change to convert a rise or fall. A change of 1 °C equals a change of 1 K or 1.8 °F/°R; temperature differences do not use the zero-point offsets.