Temperature reference
Technical unit workspace
- Quantities
- Multi
- Systems
- SI / US
Common temperature units:
- Celsius (°C): metric standard
- Fahrenheit (°F): US standard
- Kelvin (K): SI unit (science)
- Rankine (°R): engineering
Key reference points:
- Water freezes: 0°C = 32°F = 273.15K
- Body temp: 37°C = 98.6°F = 310.15K
- Water boils: 100°C = 212°F = 373.15K
- Absolute zero: -273.15°C = -459.67°F = 0K
Celsius:
Invented by Swedish astronomer Anders Celsius in 1742. Originally defined with 0° as boiling and 100° as freezing, later reversed by Carl Linnaeus. Based on the freezing and boiling points of water at standard pressure.
Fahrenheit:
Developed by German physicist Daniel Gabriel Fahrenheit in 1724. He set 0°F as the temperature of a brine solution, 32°F as the freezing point of water, and 96°F as body temperature (later refined to 98.6°F).
Kelvin:
Proposed by Lord Kelvin (William Thomson) in 1848. Based on the concept of absolute zero, the theoretical point where all thermal motion ceases. The Kelvin scale uses the same increment size as Celsius but starts at absolute zero (0K = -273.15°C).
Celsius is used for:
- Weather forecasts (most countries)
- Cooking and food safety
- Medical thermometers (most countries)
- Industrial processes
Fahrenheit is used for:
- Weather forecasts (US)
- Cooking (US recipes)
- Medical thermometers (US)
- HVAC systems (US)
Kelvin is used for:
- Scientific research and publications
- Color temperature (photography, lighting)
- Thermodynamic calculations
- Astrophysics and cosmology
Temperature Conversion Calculator
Quick answer
Formula: °F = (°C x 9/5) + 32
Reference: 0 °C = 32 °F (water freezes); 100 °C = 212 °F (water boils).
Measurement type
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Quick pairs
Jump to the most common unit combinations
Quantity
Temperature
Input unit
Celsius (°C)
Output unit
Fahrenheit (°F)
What is temperature?
Temperature measures thermal energy. Celsius (°C) and Fahrenheit (°F) are the common everyday scales; kelvin (K) is the SI unit.
Formula°F = (°C × 9/5) + 32
Key conversions
- 0 °C = 32 °F = 273.15 K (water freezes)
- 100 °C = 212 °F = 373.15 K (water boils)
- 37 °C = 98.6 °F (body temperature)
Temperature conversion pairs
This category hub covers every temperature scale. Dedicated Celsius ↔ Fahrenheit converters stay on their own URLs so this page is not a duplicate of those pair pages.
- Celsius to FahrenheitDedicated °C → °F converter with formula, chart, and examples.
- Fahrenheit to CelsiusDedicated °F → °C converter with formula, chart, and examples.
- Celsius to Fahrenheit chartHTML reference chart for common Celsius to Fahrenheit values.
- Fahrenheit to Celsius chartHTML reference chart for common Fahrenheit to Celsius values.
- Celsius temperature scaleDefinition, history, and reference points for the Celsius scale.
- Fahrenheit temperature scaleDefinition, history, and reference points for the Fahrenheit scale.
What are Temperature Measurements?
Temperature measurements quantify the degree of hotness or coldness of an object or environment. There are several scales for measuring temperature, with Celsius, Fahrenheit, and Kelvin being the most widely used.
The relationship between these units involves specific formulas: °F = (°C x 9/5) + 32, K = °C + 273.15, and °R = °F + 459.67. These relationships are fundamental in science, engineering, meteorology, cooking, medicine, and many other fields.
Learn more from NIST or Bureau International des Poids et Mesures (BIPM).
Common Temperature Conversions
| Reference Point | °C | °F | K |
|---|---|---|---|
| Absolute zero | -273.15°C | -459.67°F | 0 K |
| Water freezing | 0°C | 32°F | 273.15 K |
| Room temperature | 20°C | 68°F | 293.15 K |
| Body temperature | 37°C | 98.6°F | 310.15 K |
| Water boiling | 100°C | 212°F | 373.15 K |
| Scales equal | -40°C | -40°F | 233.15 K |
Conversion Formulas
| From | To | Formula |
|---|---|---|
| °C | °F | (°C x 9/5) + 32 |
| °F | °C | (°F - 32) x 5/9 |
| °C | K | °C + 273.15 |
| K | °C | K - 273.15 |
| °F | K | (°F - 32) x 5/9 + 273.15 |
Temperature Conversion Applications
Weather & Climate
- International weather forecast interpretation
- Climate data analysis and comparison
- Travel planning across countries
Cooking & Food Safety
- Recipe conversion between metric and imperial
- Food safety temperature thresholds
- Oven temperature settings
Science & Engineering
- Laboratory experiments and research
- Thermodynamic calculations
- Material science and industrial processes
Medicine & Healthcare
- Patient body temperature monitoring
- Medical equipment calibration
- Pharmaceutical storage requirements
Educational Resource
This educational video explains how to convert between different temperature scales including Celsius, Fahrenheit, and Kelvin with clear step-by-step examples.
Temperature Conversion Resources
Get our comprehensive temperature conversion chart showing Celsius, Fahrenheit, Kelvin and Rankine values for quick reference when you're working with temperature measurements.
Temperature Conversion FAQs
Find answers to common questions about temperature measurements and conversions.
How do you convert between Celsius and Fahrenheit?
To convert Celsius to Fahrenheit: multiply by 9/5 (or 1.8) and add 32. To convert Fahrenheit to Celsius: subtract 32 and multiply by 5/9 (or 0.5556). For example: 100°C = 212°F, and 72°F = 22.2°C. Our calculator handles these conversions automatically.
What are common temperature units?
Common temperature units include: 1) Celsius (°C) - used worldwide for everyday temperatures, 2) Fahrenheit (°F) - used in the US for everyday temperatures, 3) Kelvin (K) - the SI unit used in science, 4) Rankine (°R) - used in some engineering applications. Each unit has specific applications.
Why use different temperature scales?
Different temperature scales serve various purposes: 1) Celsius for everyday use in most countries, 2) Fahrenheit for everyday use in the United States, 3) Kelvin for scientific and thermodynamic calculations (absolute zero = 0K), 4) Rankine for certain engineering applications. The choice depends on context and regional convention.
What is absolute zero?
Absolute zero is the lowest possible temperature where all molecular motion ceases. It equals: 1) 0 Kelvin (K), 2) -273.15°C, 3) -459.67°F, 4) 0°R (Rankine). Absolute zero is a theoretical limit that cannot be reached in practice but is fundamental to thermodynamics and physics.
Temperature conversion shortcuts
Common temperature calculators, formulas and charts in one crawlable block.