Enter Temperature & Units
Result
Converted: –
Formula: –
Overview
Temperature scales can be linear (°C, °F, K) or involve offsets/slopes (Delisle, Newton, Réaumur, Rømer, Gas Mark). This converter uses Kelvin as the pivot, applying the exact formula for each pair.
Formula & Methodology
All conversions go via Kelvin (K):
$$ T_K = f_{\rm toK}(T_{\rm in}),\quad T_{\rm out} = f_{\rm fromK}(T_K)\,. $$
| Scale | Symbol | To K | From K |
|---|---|---|---|
| Celsius | °C | \(T+273.15\) | \(T-273.15\) |
| Fahrenheit | °F | \((T+459.67)\times5/9\) | \(T\times9/5-459.67\) |
| Kelvin | K | \(T\) | \(T\) |
| Rankine | °R | \(T\times5/9\) | \(T\times9/5\) |
| Delisle | °De | \(373.15 - 2T/3\) | \((373.15-T)\times3/2\) |
| Newton | °N | \(T\times100/33+273.15\) | \((T-273.15)\times33/100\) |
| Réaumur | °Ré | \(T\times5/4+273.15\) | \((T-273.15)\times4/5\) |
| Rømer | °Rø | \((T-7.5)\times40/21+273.15\) | \((T-273.15)\times21/40+7.5\) |
| Gas Mark | GM | \(T\times125/9+394.26\) | \((T-250)\,/25\) |
Examples
- 100 °C → °F: \(100×9/5+32 = 212\) °F
- 32 °F → K: \((32+459.67)×5/9 ≈ 273.15\) K
- 20 °De → °C: \((373.15-20×2/3)-273.15 ≈ -6.33\) °C
Frequently Asked Questions
What is Gas Mark?
Gas Mark is a UK oven scale—1 GM ≈ 135 °F. We convert via an offset formula.
Why go via Kelvin?
Kelvin is absolute zero–based, so all linear/offset scales map neatly through it.
Where do these formulas come from?
From the International Temperature Scale definitions (ITS-90).