| Input | From | To | Result |
|---|---|---|---|
| 0 | Celsius (°C) | Fahrenheit (°F) | 32 |
| 100 | Celsius (°C) | Kelvin (K) | 373.15 |
| -40 | Celsius (°C) | Fahrenheit (°F) | -40 |
| 300 | Kelvin (K) | Celsius (°C) | 26.85 |
This calculator converts the input to Kelvin as an intermediate base, then converts Kelvin to the target scale. This approach reduces mistakes and keeps the logic consistent.
| Scale | To Kelvin (K) | From Kelvin (K) |
|---|---|---|
| Celsius (°C) | K = °C + 273.15 | °C = K − 273.15 |
| Fahrenheit (°F) | K = (°F − 32) × 5/9 + 273.15 | °F = (K − 273.15) × 9/5 + 32 |
| Kelvin (K) | K = K | K = K |
| Rankine (°R) | K = °R × 5/9 | °R = K × 9/5 |
| Réaumur (°Ré) | K = °Ré × 1.25 + 273.15 | °Ré = (K − 273.15) × 0.8 |
| Newton (°N) | K = °N × 100/33 + 273.15 | °N = (K − 273.15) × 33/100 |
| Delisle (°De) | K = 373.15 − °De × 2/3 | °De = (373.15 − K) × 3/2 |
| Rømer (°Rø) | K = (°Rø − 7.5) × 40/21 + 273.15 | °Rø = (K − 273.15) × 21/40 + 7.5 |
Tip: Kelvin should not be negative in physical contexts. This tool will still compute mathematically for any numeric input.
- Enter a temperature value (decimals and scientific notation are supported).
- Select the source scale in From Unit.
- Select the destination scale in To Unit.
- Pick your preferred decimal precision.
- Click Calculate to see results above the form.
- Use Download CSV or Download PDF to export.
1) Why temperature conversion matters
Temperature is a core variable in physics, linking directly to energy, phase changes, reaction rates, and sensor behavior. Different fields still publish in different scales, so fast and accurate conversion helps you compare datasets, validate models, and avoid unit errors in reports.
2) Fixed points used by common scales
Many conversions reference water benchmarks. At standard pressure, water freezes at 0 °C and boils at 100 °C, which correspond to 32 °F and 212 °F. A more precise thermodynamic reference is the triple point of water at 273.16 K, often used for calibration work.
3) Kelvin as the scientific baseline
Kelvin is the thermodynamic scale where 0 K represents absolute zero, the lower limit of thermal motion. In this calculator, every input is first mapped into Kelvin, then converted to the requested output. This keeps each conversion consistent and reduces chained rounding.
4) Offsets and scaling are both important
Some scales differ by an offset and a multiplier. For example, converting from Celsius to Fahrenheit uses both: °F = (°C × 9/5) + 32. Others are pure scaling, like Rankine and Kelvin: °R = K × 9/5. Understanding which type you are using helps you spot mistakes quickly.
5) Negative values and physical interpretation
Negative values are normal on Celsius and Fahrenheit, especially in weather and cryogenics. However, Kelvin and Rankine should not be negative in physical contexts. If you enter a value below absolute zero, the tool will still compute mathematically, but the result is not physically meaningful.
6) Less common scales included for completeness
This calculator also supports several historical scales that still appear in legacy literature. Réaumur divides the freezing-to-boiling interval into 80 degrees. Newton uses 33 degrees for the same interval. Delisle is reversed, decreasing as temperature rises. Rømer uses an offset (notably 7.5 °Rø at freezing), which makes careful conversion essential.
7) Precision, rounding, and reporting
Scientific reporting should match your measurement uncertainty. If a probe is accurate to ±0.5 °C, showing ten decimals is misleading. Use the precision selector to keep outputs readable, and remember that rounding is best applied once at the final stage, not repeatedly.
8) Export-ready outputs for lab notes
For documentation, export the full scale table. CSV is ideal for spreadsheets, while PDF is convenient for attaching a clean snapshot to lab notebooks or project reports. Both exports help preserve the exact inputs, unit choices, and formatted values used in your calculation.
1) Why does the calculator convert through Kelvin?
Kelvin provides a consistent thermodynamic base. Converting input to Kelvin first and then to the target scale avoids chaining multiple custom formulas and reduces chances of inconsistency across scales.
2) What is the relationship between Celsius and Kelvin?
The scales have the same step size, but different zeros. The conversion is K = °C + 273.15 and °C = K − 273.15.
3) Why is −40 a popular example?
Because −40 °C equals −40 °F. It is a simple check that the conversion logic and offsets are behaving correctly.
4) Can Kelvin be negative?
In physical terms, no. Absolute zero is 0 K. Values below that are not physically meaningful, even though the calculator can still compute them as a mathematical transformation.
5) Which precision should I choose?
Pick a precision that matches your instrument and reporting needs. For most engineering work, 1–3 decimals is enough. Use more only when your measurements and required standards justify it.
6) What are Rankine and why is it included?
Rankine is an absolute scale like Kelvin, but it uses Fahrenheit-sized degrees. It is used in some thermodynamics and aerospace contexts, especially in older references and certain engineering conventions.
7) What does the exported table contain?
The export includes your primary conversion plus a full table of equivalent values across all supported scales. This is useful for cross-checking, sharing results, and keeping a consistent record in documentation.