40 Fahrenheit to Rankine – Easy Conversion Explained

40 degrees Fahrenheit is equal to 499.67 degrees Rankine.

To convert Fahrenheit to Rankine, you add 459.67 to the Fahrenheit temperature, because the Rankine scale starts at absolute zero, just like Kelvin, but uses Fahrenheit degrees. This means the Rankine scale shifts the Fahrenheit scale upward by 459.67 degrees.

Conversion Tool

Conversion Formula

The formula for converting a temperature from Fahrenheit to Rankine is:

Rankine (°R) = Fahrenheit (°F) + 459.67

This works because the Rankine scale is an absolute temperature scale, meaning it starts at absolute zero, just like Kelvin. But while Kelvin uses Celsius degrees, Rankine uses Fahrenheit degree increments. So you take the Fahrenheit temperature and add 459.67, which is the offset to get to absolute zero in Rankine.

Example calculation:

• Given 40°F
• Add 459.67: 40 + 459.67 = 499.67
• Therefore, 40°F equals 499.67°R

Conversion Example

• Convert 70°F to Rankine:
  • Start with 70°F
  • Add 459.67: 70 + 459.67 = 529.67
  • Result: 529.67°R
• Convert 0°F to Rankine:
  • Start with 0°F
  • Add 459.67: 0 + 459.67 = 459.67
  • Result: 459.67°R
• Convert -40°F to Rankine:
  • Start with -40°F
  • Add 459.67: -40 + 459.67 = 419.67
  • Result: 419.67°R
• Convert 100°F to Rankine:
  • Start with 100°F
  • Add 459.67: 100 + 459.67 = 559.67
  • Result: 559.67°R

Conversion Chart

Use this chart to quickly find the Rankine equivalent of Fahrenheit temperatures between 15 and 65 degrees by simply adding 459.67 to the Fahrenheit value. You can match your temperature in the left column and read across to get the corresponding Rankine temperature.

Related Conversion Questions

• How many Rankine degrees equal 40 Fahrenheit?
• What is the formula to convert 40°F into Rankine?
• Is 40 Fahrenheit hotter or colder than 500 Rankine?
• Can I convert 40 degrees Fahrenheit directly to Rankine without a calculator?
• What temperature in Rankine matches freezing point if Fahrenheit is 40?
• Why does 40°F convert to such a high Rankine value?
• How does the Rankine scale compare to Fahrenheit at 40 degrees?

Conversion Definitions

Fahrenheit: The Fahrenheit scale is a temperature measurement system where water freezes at 32 degrees and boils at 212 degrees under standard atmospheric pressure. Used primarily in the United States, it divides the interval between freezing and boiling of water into 180 equal parts, called degrees Fahrenheit.

Rankine: The Rankine scale is an absolute temperature scale used in engineering, especially thermodynamics, that starts at absolute zero. It uses increments equal to degrees Fahrenheit but shifted so that 0 Rankine is absolute zero, making it useful for calculations involving heat and energy.

Conversion FAQs

Why do I add 459.67 to Fahrenheit to get Rankine?

Because the Rankine scale starts at absolute zero, which is -459.67°F, you must add 459.67 to any Fahrenheit temperature to shift the zero point. This aligns the Fahrenheit scale with absolute zero reference point required for thermodynamic calculations.

Can negative Fahrenheit values be converted to Rankine?

Yes, negative Fahrenheit temperatures convert to Rankine by adding 459.67. Since Rankine cannot be below zero (absolute zero), the result will always be positive, even if Fahrenheit is negative.

Is Rankine used outside engineering fields?

Rankine is rare outside of engineering and thermodynamics. It mainly appears in scientific contexts, especially in the US, where absolute temperature scales using Fahrenheit increments are needed for precise calculations.

How precise is the formula Fahrenheit + 459.67?

This formula is exact for converting between Fahrenheit and Rankine because both scales use the same size increments, differing only by their zero points. No approximation occurs in this conversion method.

Does converting Fahrenheit to Rankine affect temperature differences?

No, temperature differences stay the same because both scales have identical degree sizes. Only the starting point changes, so adding 459.67 shifts the scale but doesn’t alter differences between temperatures.

Last Updated : 22 June, 2025

Sandeep Bhandari

Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.