Temperature Converter: Celsius, Fahrenheit, Kelvin, Rankine and historical scales
Scientific conversion tool across 8 temperature scales: Celsius (°C), Fahrenheit (°F), Kelvin (K), Rankine (°R), Réaumur (°Ré), Delisle (°De), Newton (°N) and Rømer (°Rø). Supports absolute mode (temperature values) and delta mode (temperature differences).
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When to use this tool
Quick conversion across scales in physics, chemistry, biology and geosciences: lab work (incubations, PCR), thermodynamics (Δ°C ↔ ΔK ↔ Δ°F for heat capacities and coefficients), industrial processes using imperial scales (°F, °R), cryogenics (Kelvin) and comparison with historical scales (Réaumur, Newton).
How it works
Type a value, pick the source and target scales, and the result appears instantly next to the step-by-step formula. The ⇄ button swaps source and target, and the 'Show all equivalents' panel shows the value across all 8 scales at once. The Absolute / Δ Difference selector distinguishes two situations that convert differently: in absolute mode you convert a specific temperature (for example 25 °C to °F); in 'Δ Difference' mode you convert a change or temperature gap, where the zero points of each scale don't carry over —only the size of a degree does— so Δ°C = ΔK but Δ°F = (5/9) × Δ°C, the key distinction when working with heat capacities or coefficients. In absolute mode, a value below the chosen scale's absolute zero triggers a warning.