Free Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin, and Rankine instantly. 100% free, no signup, works offline. Perfect for science, cooking, and engineering.

From:

°C

To (optional):

Celsius

0.00

°C

Fahrenheit

32.00

°F

Kelvin

273.15

Rankine

491.67

°R

🔒💻

Privacy First — No Server Uploads
All conversions happen locally in your browser. No data is sent to any server. No signup, no tracking, no storage.

Temperature Converter: Celsius, Fahrenheit, Kelvin, and Rankine

Our free temperature converter handles the most common temperature scales and also includes Rankine (°R) — the absolute scale used in thermodynamics and certain engineering fields. Whether you're a student, scientist, chef, traveler, or HVAC technician, this online temperature calculator gives you instant, accurate conversions without uploading your data.

🌡️ Four Temperature Scales

Celsius, Fahrenheit, Kelvin, and Rankine — all in one tool.

📐 Precise Formulas

Uses standard conversion formulas with up to 4 decimal places of precision.

🔒 100% Local Processing

Your data never leaves your device — complete privacy.

⚡ No Signup Required

Use the tool instantly, no registration, no payment.

📱 Works on Any Device

Responsive design for desktop, tablet, and mobile.

🔁 Bidirectional Conversion

Select any "from" unit and see all others update automatically.

How to Use This Temperature Converter

1. Select the unit you are converting from (Celsius, Fahrenheit, Kelvin, or Rankine).
2. Enter a numeric value in the input field.
3. (Optional) Choose a target unit if you want to see a specific conversion, or just watch all four results update instantly.
4. Results appear in real time — no clicking required.

Complete Conversion Formulas

Celsius (°C)
- To Fahrenheit: (°C × 9/5) + 32 = °F
- To Kelvin: °C + 273.15 = K
- To Rankine: (°C + 273.15) × 9/5 = °R

Fahrenheit (°F)
- To Celsius: (°F − 32) × 5/9 = °C
- To Kelvin: (°F − 32) × 5/9 + 273.15 = K
- To Rankine: °F + 459.67 = °R

Kelvin (K)
- To Celsius: K − 273.15 = °C
- To Fahrenheit: (K − 273.15) × 9/5 + 32 = °F
- To Rankine: K × 9/5 = °R

Rankine (°R)
- To Celsius: (°R − 491.67) × 5/9 = °C
- To Fahrenheit: °R − 459.67 = °F
- To Kelvin: °R × 5/9 = K

Frequently Asked Questions

What is Rankine and why would I need it?

Rankine is an absolute temperature scale used primarily in thermodynamics and certain engineering fields (especially in the US). Like Kelvin, it starts at absolute zero, but uses the Fahrenheit increment. It's useful for calculations involving gas laws and heat engines.

Is this temperature converter accurate for scientific work?

Yes. The tool uses standard scientific formulas with 4 decimal places of precision, which is sufficient for most lab work, engineering, and educational purposes.

Do I need an internet connection?

Once loaded, the temperature converter works entirely offline. All calculations are performed locally in your browser using JavaScript.

What are the freezing and boiling points of water in Rankine?

Water freezes at 491.67°R and boils at 671.67°R (at standard atmospheric pressure).

Learn how to use this tool correctly by reading our step-by-step tutorial.

View Detailed Tutorial →