Temperature Converter Guide: Switch Between °C, °F, K & °R
Whether you are checking tomorrow's weather, following a baking recipe from another country or reading a science article, you will constantly see temperatures in different units. Most of the world uses Celsius (°C), the United States often shows Fahrenheit (°F), scientists work with Kelvin (K), and engineers sometimes prefer Rankine (°R). This page combines everything in one place so you can convert between all four scales in seconds.
Type any value in the temperature converter at the top of this page, choose your "from" and "to" units, and the result updates instantly. The "All Scales" box shows the same value in every unit — ideal if you want to see Celsius, Fahrenheit, Kelvin and Rankine side by side.
If you often work with numbers, you might also like our Percentage Calculator, Currency Converter or Area Calculator for other everyday calculations.
What Each Temperature Scale Means
Celsius (°C) is built around water: 0°C is the freezing point and 100°C is the boiling point at normal atmospheric pressure. It's the default scale in weather apps, school science and everyday life across most of the world.
Fahrenheit (°F) also uses water, but with different reference points: water freezes at 32°F and boils at 212°F. People in the US think of 70°F as comfortable room temperature and 32°F as the freezing point.
Kelvin (K) is the scientific "absolute" scale. It starts at absolute zero (0 K), the theoretical temperature where molecular motion stops. The size of one Kelvin is the same as one degree Celsius, but there are no negative values — 0°C is 273.15 K.
Rankine (°R) is an absolute scale like Kelvin, but based on Fahrenheit-sized degrees. It is mainly used in thermodynamics and some engineering fields in the US.
Celsius ⇄ Fahrenheit
°F = (°C × 9/5) + 32 | °C = (°F − 32) × 5/9
Celsius ⇄ Kelvin
K = °C + 273.15 | °C = K − 273.15
Fahrenheit ⇄ Kelvin
K = (°F − 32) × 5/9 + 273.15 | °F = (K − 273.15) × 9/5 + 32
Celsius ⇄ Rankine
°R = (°C + 273.15) × 9/5
Fahrenheit ⇄ Rankine
°R = °F + 459.67
Everyday Examples: Weather, Cooking & Health
If you are travelling from Europe to the US and your app shows 28°C, that equals 82.4°F — hot enough for a T-shirt. On the other side, −5°C is 23°F, which means ice, frost and winter jackets.
In the kitchen, a typical European recipe that says 180°C corresponds to 356°F on an American oven. Getting this wrong and setting the oven to 180°F would give you a lukewarm box, not a proper baking temperature. For body temperature, a normal reading is around 37°C (98.6°F) and a high fever of 40°C is 104°F. Always consult a healthcare professional for medical advice.
If you are tracking health metrics, you may also find our BMI Calculator and Calorie Calculator helpful.
Weather:
• Cool day – 10°C = 50°F
• Warm holiday weather – 25°C = 77°F
• Heat warning – 35°C = 95°F
Cooking:
• Slow roast – 150°C = 302°F
• Standard baking – 180°C = 356°F
• Pizza oven – 250°C = 482°F
Home & appliances:
• Fridge – about 4°C = 39°F
• Freezer – about −18°C = 0°F
• Comfortable room – 20–22°C = 68–72°F
Tips for Accurate Temperature Conversion
- Always include the offset when converting between Celsius and Fahrenheit. It's never just "× 2" or "÷ 2" — you must subtract or add 32 as the formulas show.
- Watch the minus sign for cold temperatures. −10°C converts to 14°F — the sign matters a lot in winter.
- Use rough rules only for quick checks. Doubling °C and adding 30 gives a fast estimate (20°C ≈ 70°F), but rely on the full formula for accuracy.
- Remember Kelvin has no degree symbol. Write 293.15 K, not 293.15°K. This is standard in science and engineering.
- For precise work, keep extra decimals. The tool shows up to 6 decimal places so you can safely use the results in spreadsheets, lab notes or reports.
If you need other unit conversions, try the cm to inches converter or the KM to Miles converter alongside your temperature data.
Temperature Converter – Frequently Asked Questions
How do I use this temperature converter?
Type your value into the first box, pick the "From" unit (Celsius, Fahrenheit, Kelvin or Rankine) and choose the "To" unit. The answer updates instantly and the "All Scales" section shows the same temperature in every unit at once.
Can I convert between Celsius and Fahrenheit for cooking?
Yes. This tool is perfect for oven temperatures and food safety checks. For example, you can quickly turn 180°C into 356°F or confirm that 165°F is about 73.9°C, a common safe internal temperature for cooked chicken.
Does this calculator support Kelvin and Rankine for science and engineering?
It does. You can convert directly between Kelvin, Rankine, Celsius and Fahrenheit. This is useful for thermodynamics, gas laws, heat transfer and any physics or engineering problems that use absolute temperature.
How accurate are the results from this temperature converter?
The calculator uses standard, widely accepted conversion formulas with full double-precision math in your browser. Results are shown to six decimal places so you can safely copy them into lab reports, spreadsheets or technical documents.
Can I download or save my temperature conversions?
Yes. After you make a few conversions, use the TXT or CSV buttons in the "Conversion History" card. You will get a file with your inputs, outputs, units and timestamps — ideal for homework, research notes or project documentation.
What is a quick way to estimate Celsius to Fahrenheit in my head?
A handy rough rule is: °F ≈ (°C × 2) + 30. It is not exact, but it gets you close enough for casual weather comparisons. For anything serious — cooking, health, science or engineering — use the exact formulas or this converter.
When should I think in Kelvin instead of Celsius or Fahrenheit?
Use Kelvin whenever you work with scientific formulas that involve absolute temperature (for example gas laws or thermodynamics). Kelvin starts at absolute zero, so temperatures are always positive, which keeps the math cleaner.
Which other calculators work well with this temperature converter?
Many users open this page alongside our Energy Converter, Time Converter and Budget Calculator when planning projects that combine heating, timing and costs.