Convert temperatures between all four scales: Celsius, Fahrenheit, Kelvin, and Rankine. Visual thermometer, simultaneous conversion, reference temperature table with 12 key points, and quick conver...
Temperature conversion is one of the most common unit conversions in daily life and science. The United States uses Fahrenheit for weather, cooking, and everyday temperature references, while most of the world uses Celsius. Scientists and engineers frequently work in Kelvin, the SI base unit for thermodynamic temperature.
This converter handles all six directions between Celsius, Fahrenheit, and Kelvin. Simply select the conversion you need, enter your temperature value, and get an instant result with both precise and rounded outputs. No need to remember the formulas — the tool does the math for you.
Whether you are reading a recipe from a British cookbook, interpreting weather forecasts while traveling abroad, adjusting lab equipment to a specific Kelvin temperature, or helping your child with a science assignment, this tool gives you accurate conversions in seconds. Bookmark it for quick reference whenever temperatures come up in your daily life. Check the example with realistic values before reporting.
Temperature conversion formulas are not as simple as multiplying by a factor — they involve offsets (32 for Fahrenheit, 273.15 for Kelvin) that make mental math unreliable. This calculator eliminates errors and supports all three major scales in every direction. It is especially handy for cooking (oven temperatures), travel (weather forecasts), and science (thermodynamic calculations).
Celsius to Fahrenheit: °F = (°C × 9/5) + 32 Fahrenheit to Celsius: °C = (°F − 32) × 5/9 Celsius to Kelvin: K = °C + 273.15 Kelvin to Celsius: °C = K − 273.15 Fahrenheit to Kelvin: K = (°F − 32) × 5/9 + 273.15 Kelvin to Fahrenheit: °F = (K − 273.15) × 9/5 + 32
Result: 212 °F
100°C is the boiling point of water at standard atmospheric pressure. Using the formula: °F = (100 × 9/5) + 32 = 180 + 32 = 212°F. This is one of the most well-known temperature reference points.
Daniel Gabriel Fahrenheit introduced his scale in 1724, setting 0°F as the freezing point of a brine solution and 96°F as human body temperature (later revised to 98.6°F). Anders Celsius proposed his scale in 1742 with 0° as the boiling point and 100° as the freezing point — this was later inverted to the modern convention. Lord Kelvin introduced the absolute temperature scale in 1848, anchoring it at absolute zero.
Fahrenheit is common in the United States for weather, cooking, and HVAC. Celsius is the global standard for weather, medicine, and most industries. Kelvin is used in scientific research, engineering thermodynamics, and any context where ratios of temperatures matter (gas laws, thermal radiation, etc.).
- −40°C = −40°F (intersection point) - 0°C = 32°F (water freezes) - 20°C = 68°F (room temperature) - 37°C = 98.6°F (body temperature) - 100°C = 212°F (water boils) - 0 K = −273.15°C = −459.67°F (absolute zero)
Multiply the Celsius temperature by 9/5 (or 1.8), then add 32. For example, 25°C × 1.8 + 32 = 77°F. The multiplication scales the degree size, and adding 32 accounts for the offset between the two scales.
Absolute zero is 0 Kelvin (−273.15°C or −459.67°F). It is the theoretical lowest temperature where all molecular motion ceases. No object can be cooled below absolute zero.
The Fahrenheit scale was developed by Daniel Gabriel Fahrenheit in 1724 and adopted in English-speaking countries. While most nations switched to Celsius after metrication, the US retained Fahrenheit for everyday use due to tradition and the scale's finer granularity for weather temperatures.
Celsius and Kelvin use the same degree size, but their zero points differ. 0°C is the freezing point of water; 0 K is absolute zero (−273.15°C). To convert, simply add or subtract 273.15.
The two scales intersect at −40 degrees. That is, −40°C = −40°F. This is the only temperature where both scales give the same numeric reading.
Yes — double the Celsius value and add 30. For example, 20°C ≈ 2 × 20 + 30 = 70°F (actual: 68°F). This shortcut is accurate within a few degrees for everyday temperatures.