Primary formula
Absolute mode applies offsets to kelvin; interval mode converts only scale size.
Unit converter
Temperature Converter
Convert absolute temperatures or temperature intervals across Celsius, Fahrenheit, kelvin and Rankine.
Last reviewed: July 6, 2026Unit conversion engine v1.1.0
Unit converter
Temperature Converter
Convert one value between supported units, then compare the same source value against all units in this dimension.
Decimal.js unit engine
Enter a value and choose Convert to show the result and convert-all table.
Formula and assumptions
Input assumptions
Conversions use the central NexaCalc unit registry. Displayed decimals are rounded after calculation. No external conversion service is queried.
Precision note
Decimal.js is used for unit conversion arithmetic. Intermediate values are not rounded before display formatting.
Unit conversion flow
Validate
Check value syntax, selected dimension and compatible source and target units.
Normalize
Convert the source value to the dimension base unit or special reciprocal/density bridge when needed.
Convert
Convert to the selected target unit, including affine temperature offsets, fuel reciprocal handling or cooking density when needed.
Explain
Display rounded, scientific, visual and convert-all results with unit-system labels.
What is the Temperature Converter?
The Temperature Converter converts Celsius, Fahrenheit, kelvin and Rankine values. It uses the central NexaCalc unit registry so constants are shared across the Conversion category rather than copied into each page.
The tool is for unit conversion only. It does not solve physics, engineering, nutrition or finance equations beyond changing a value from one supported unit to another.
How to use the Temperature Converter
Enter a value, choose the source unit and target unit, then select Convert. Use Swap to reverse the units, and use the convert-all table to compare the same value across supported units.
The significant-digits control changes display precision only. Internal calculations use Decimal.js with higher precision before formatting.
Formula and definitions
Absolute temperature conversions use affine formulas with offsets. Temperature interval mode converts only the size of a temperature difference and does not apply offsets.
Temperature can require offsets, so absolute temperatures and temperature intervals are handled as different modes.
Calculation example
0 degrees Celsius equals 32 degrees Fahrenheit, and -40 degrees Celsius equals -40 degrees Fahrenheit.
The convert-all table repeats the same source value across every supported unit, which makes it easier to compare systems without changing the original input.
Changing significant digits only changes display precision. The conversion is recalculated from the original source value each time.
Supported units
Temperature Converter currently supports: kelvin, degree Celsius, degree Fahrenheit, degree Rankine.
Units are grouped by system where possible so SI, metric, US customary, Imperial, scientific and other definitions stay readable.
Result visual
The visual output appears only after Convert is selected. It compares the entered source value and target result using the actual calculated output rather than showing a static decoration.
For dimensions with special meaning, such as fuel economy, data transfer or cooking measurement, the visual labels explain the interpretation instead of assigning misleading health, quality or performance categories.
Important distinctions
US customary, Imperial, SI, metric, scientific and international units are labelled separately where the names are easy to confuse.
If two units share a familiar name but use different definitions, NexaCalc keeps the unit-system label visible in the selector and convert-all table.
- Absolute temperatures below 0 K are rejected.
- Temperature intervals do not apply Celsius or Fahrenheit offsets.
- Kelvin is the SI base unit for thermodynamic temperature.
Common use cases
Use the Temperature Converter for quick checks, spreadsheet verification, educational examples, product measurements and cross-system documentation.
For workflows that need live market, weather, nutrition or engineering data, use a dedicated calculator that includes those assumptions instead of treating this unit page as a data source.
Precision and rounding
Decimal.js handles the arithmetic so repeating decimals and very small or very large values remain stable before formatting.
Some source standards define exact conversion factors. Other values are conventional approximations, so the page labels references and keeps critical-use warnings visible.
Limitations
Displayed decimal values may be rounded. Verify critical engineering, scientific, medical, commercial or legal measurements independently.
This page does not validate whether a converted number is appropriate for a design, recipe, shipment, laboratory procedure or financial decision.
Frequently asked questions
Does the Temperature Converter use a live API?
No. Unit conversions run locally from static definitions in the NexaCalc unit registry.
Are results exact?
Many unit definitions are exact, but displayed decimals are rounded to the selected significant digits. The result also shows scientific notation.
Why does the Temperature Converter show a convert-all table?
The table lets you compare the same source value against every supported unit in the dimension without re-entering the number.
Why are some units labelled US or Imperial?
Some names overlap but have different definitions. NexaCalc labels those systems separately to avoid mixing US customary and Imperial units.
Why is temperature different?
Temperature has offsets between absolute scales, so Celsius and Fahrenheit cannot be handled as simple multiplication in absolute mode.
What do significant digits change?
They change how many meaningful digits are displayed. They do not change the stored unit factors or the original input value.
Can I use scientific notation?
Yes. Inputs such as 1e-6 are supported, and you can display results in standard or scientific notation.
Does the visual affect the answer?
No. The visual is a calculated explanation of the output. The numeric result and table come from the same deterministic conversion function.
Can this replace a professional standard?
No. NexaCalc is useful for everyday and educational conversion, but critical work should be verified against the governing standard or instrument.
Are all units in one shared registry?
Yes. The conversion pages use one central registry to keep factors consistent across tools.
References
- BIPM, The International System of Units SI Brochure, 9th edition and updates. Source.
- NIST, Guide for the Use of the International System of Units and unit conversion factors. Source.
- NIST, CODATA and SI exact defining constants for scientific unit context. Source.
- NIST Handbook 44, Appendix C, General Tables of Units of Measurement. Source.
- IEC, binary prefixes for data units such as KiB, MiB and GiB. Source.
- USDA FoodData Central, ingredient-specific nutrition and density context for cooking measurements. Source.
Conversion reference set v1.1 reviewed July 6, 2026.
Educational disclaimer
This calculator provides mathematical results from the values, conventions and methods you enter. Verify important academic, engineering or professional work independently.