Temperature converter
Converts temperatures between °C, °F, and K.
30 °C is 86 °F.
- Input
Provenance
- Computed by
- units.temperature.convert 1.0.0, core 0.1.0
- Model
- Exact unit definitions
- Accuracy
- Exact to double precision: each conversion is one correctly rounded ratio of exact definitions
- Notes
- None
- Cites
- National Institute of Standards and Technology, Guide for the Use of the International System of Units (SI), NIST Special Publication 811
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: Exact unit definitions
Accuracy: Exact to double precision: each conversion is one correctly rounded ratio of exact definitions
When to use this: Use this for a temperature that is a reading rather than a change: an outside air temperature against a performance chart, a forecast in one scale against a limit in another, a surface temperature against an operating range. It is the tool for a point on the scale, and it applies the offsets those scales are built on, which is exactly what a change in temperature must not have.
Limitations: This converts temperatures, not differences between them, and the two are different conversions: 10 °C is 50 °F, but a rise of 10 °C is a rise of 18 °F. Using this where a deviation is meant -- an ISA deviation, a lapse, a spread -- puts the answer out by the whole offset, 32 degrees between Fahrenheit and Celsius, and the temperature-difference converter next door is the one for that. Below absolute zero is refused rather than converted, since no scale means anything there.
Worked example: 30 °C in °F. Source: Exact unit definitions (NIST SP 811 Appendix B).
You enter
- To unit
- degF
- Value
- 30 °C
You get
- Converted
- 86 °F
- Input
- 30 °C
Review: Not yet independently reviewed by a metrologist.
Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Checked against: 22 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, National Institute of Standards and Technology, 2008 edition. Appendix B.8, Factors for units listed alphabetically.