Online Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin, and Rankine instantly. Free, accurate, and 100% private — no uploads, no signup.

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.

Online Temperature Converter: Celsius, Fahrenheit, Kelvin, and Rankine

Our online temperature converter is the ultimate tool for converting between the four most important temperature scales. Whether you're a student studying thermodynamics, a chef adjusting oven temperatures, a traveler checking international weather, or an engineer working with Rankine, this tool provides instant, accurate conversions — all without uploading your data.

🌡️ Four Scales in One

Celsius, Fahrenheit, Kelvin, and Rankine — all supported with precise formulas.

🔁 Bidirectional Conversion

Convert from any scale to any other. See all four results at once.

📐 Accurate Formulas

Uses standard thermodynamic formulas with 4‑decimal precision.

🔒 100% Private

All calculations run locally in your browser — no uploads, no servers.

⚡ No Signup

Use the tool instantly. No registration, no email, no payment.

📱 Works Anywhere

Responsive design works on desktop, tablet, and mobile.

How to Use This Online Temperature Converter

1. Select the unit you're converting from (Celsius, Fahrenheit, Kelvin, or Rankine).
2. Type a numeric value in the input field.
3. (Optional) Choose a target unit if you want a focused conversion.
4. All four temperature values update automatically — no button pressing needed, though a "Convert" button is also provided.

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 when is it used?

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 Fahrenheit increments. It's essential for gas law calculations and heat engine analysis.

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.

Does this tool work offline?

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 →