Convert ppm/°F to Per Kelvin (ppm/°F to K⁻¹)
1 ppm per degree Fahrenheit (ppm/°F) = 0.0000018 per kelvin (K⁻¹). 1 K⁻¹ = 555555.5556 ppm/°F. Example: 15 ppm/°F = 15 × 0.0000018 = 0.000027 K⁻¹.
Also searched as ppm per degree Fahrenheit to K⁻¹, ppm per degree Fahrenheit in K⁻¹, ppm per degree Fahrenheit into per kelvin, ppm/°F to K⁻¹, ppm/°F in per kelvin, ppm/°F into per kelvin, ppm per degree Fahrenheit to per kelvin, ppm/°F to per kelvin converter and how many per kelvin in a ppm per degree Fahrenheit.
1 ppm/°F = 0.0000018 K⁻¹
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk ppm per degree Fahrenheit to per kelvin converter to paste a column from Excel.
How to Convert ppm/°F to Per Kelvin
- 1 ppm/°F = 0.0000018 K⁻¹
- 1 K⁻¹ = 555555.5556 ppm/°F
- Example: convert 15 ppm/°F to K⁻¹: 15 ppm/°F = 15 × 0.0000018 K⁻¹ = 0.000027 K⁻¹
Formula
K⁻¹ = ppm/°F × 0.0000018
or K⁻¹ = ppm/°F ÷ 555555.5555556
Derivation from SI units:
- 1 ppm/°F = 10⁻⁶ /°F = 1.8 × 10⁻⁶ K⁻¹ = 1 µin/(in·°F)
- The SI unit of the coefficient of thermal expansion: relative change in length (m/m) per kelvin
Both units are defined exactly, so the factor is exact. ppm/°F definition: ppm per degree Fahrenheit; Per Kelvin definition: per kelvin.
Worked examples
- A reading of 5 ppm/°F converts to 0.000009 K⁻¹.
5 ppm/°F × 0.0000018 = 0.000009 K⁻¹ - A value of 9.6 ppm/°F is 0.00001728 K⁻¹.
9.6 ppm/°F × 0.0000018 = 0.00001728 K⁻¹
ppm/°F to Per Kelvin conversion table
| ppm/°F | Per Kelvin (K⁻¹) |
|---|---|
| 0.3 ppm/°F | 5.4 × 10⁻⁷ K⁻¹ |
| 1 ppm/°F | 0.0000018 K⁻¹ |
| 3 ppm/°F | 0.0000054 K⁻¹ |
| 5 ppm/°F | 0.000009 K⁻¹ |
| 6.5 ppm/°F | 0.0000117 K⁻¹ |
| 7 ppm/°F | 0.0000126 K⁻¹ |
| 9.6 ppm/°F | 0.00001728 K⁻¹ |
| 12.8 ppm/°F | 0.00002304 K⁻¹ |
| 20 ppm/°F | 0.000036 K⁻¹ |
| 50 ppm/°F | 0.00009 K⁻¹ |
Where it's used
ppm/°F are used for US material and alloy datasheets, while per kelvin appear in linear expansion ΔL = α L ΔT. Both measure coefficient of thermal expansion (α, CTE), so the conversion is a fixed factor.
ppm/°F to other thermal expansion coefficient units
| Conversion | 1 ppm/°F equals |
|---|---|
| ppm per degree Fahrenheit to per kelvin | 0.0000018 K⁻¹ |
| ppm per degree Fahrenheit to ppm per kelvin | 1.8 ppm/K |
| ppm per degree Fahrenheit to per degree Celsius | 0.0000018 °C⁻¹ |
| ppm per degree Fahrenheit to per degree Fahrenheit | 0.000001 °F⁻¹ |
Frequently asked questions
How many per kelvin are in 1 ppm per degree Fahrenheit?
1 ppm/°F = 0.0000018 K⁻¹.
How do I convert ppm per degree Fahrenheit to per kelvin?
Multiply the value in ppm/°F by 0.0000018, or divide it by 555555.5556. For example, 15 ppm/°F × 0.0000018 = 0.000027 K⁻¹.
Is the ppm/°F to K⁻¹ conversion exact?
Yes. Both units are defined exactly, and 1 ppm/°F is exactly 0.0000018 K⁻¹.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "degree Fahrenheit".
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, degree Celsius.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert ppm/°F to Per Kelvin (ppm/°F to K⁻¹). Retrieved October 25, 2026, from https://scientificconverters.com/thermal-expansion/ppm-per-degree-fahrenheit-to-per-kelvin/
IEEE
Scientific Converters, "Convert ppm/°F to Per Kelvin (ppm/°F to K⁻¹)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/thermal-expansion/ppm-per-degree-fahrenheit-to-per-kelvin/