Temperature Converter

Instantly convert between Celsius, Fahrenheit, Kelvin, and Rankine — with formulas, reference table, and real-time results.

4 Scales Instant Results Offline Ready Mobile Friendly

Water Boils: 100 °C / 212 °F | Water Freezes: 0 °C / 32 °F | Body Temp: 37 °C / 98.6 °F | Absolute Zero: −273.15 °C

Convert Temperature

Enter a value in any field below — all other scales update automatically.

Enter Temperature

Celsius (°C)

°C

Fahrenheit (°F)

°F

Kelvin (K)

Rankine (°R)

°R

Results

°C

Celsius

—

°F

Fahrenheit

—

Kelvin

—

°R

Rankine

—

°C

—

°F

—

°R

—

Temperature Reference Chart

Common temperature benchmarks across all four scales for quick reference.

Reference Point	°C Celsius	°F Fahrenheit	K Kelvin	°R Rankine
Absolute Zero	−273.15	−459.67	0	0
Water Freezes	0	32	273.15	491.67
Room Temperature	25	77	298.15	536.67
Human Body Temp	37	98.6	310.15	558.27
Water Boils	100	212	373.15	671.67
Oven (Moderate)	180	356	453.15	815.67
Surface of the Sun	5,500	9,932	5,773.15	10,391.67

About This Temperature Converter

This free online temperature converter lets you instantly convert any temperature between Celsius (°C), Fahrenheit (°F), Kelvin (K), and Rankine (°R). All conversions happen instantly in your browser — no data is sent to any server.

Whether you're a student, scientist, chef, or traveller, this tool gives you accurate results with full conversion formulas and a visual thermometer for quick comparison.

Conversion Formulas

All conversions are derived from the Celsius base. Here are the key formulas:

From Celsius (°C)


            °F = (°C × 9/5) + 32

            K  = °C + 273.15

            °R = (°C + 273.15) × 9/5

From Fahrenheit (°F)


            °C = (°F − 32) × 5/9

            K  = (°F + 459.67) × 5/9

            °R = °F + 459.67

From Kelvin (K)


            °C = K − 273.15

            °F = (K × 9/5) − 459.67

            °R = K × 9/5

From Rankine (°R)


            °C = (°R − 491.67) × 5/9

            °F = °R − 459.67

            K  = °R × 5/9

Understanding the Four Temperature Scales

Celsius (°C) — Developed by Anders Celsius in 1742. Based on water freezing at 0 °C and boiling at 100 °C. Used in most countries worldwide.
Fahrenheit (°F) — Developed by Daniel Fahrenheit in 1724. Water freezes at 32 °F and boils at 212 °F. Primarily used in the United States.
Kelvin (K) — The SI unit of thermodynamic temperature. Absolute zero (0 K) means no thermal energy. Widely used in science and engineering.
Rankine (°R) — Similar to Kelvin but uses Fahrenheit-degree increments. Absolute zero is 0 °R. Used in some engineering fields in the US.

Key Features

Live Conversion: Type in any field and all others update instantly.
Visual Thermometers: See a proportional thermometer chart for quick comparison.
Copy to Clipboard: One-click copy for any result value.
Reference Table: Common benchmarks across all four scales.
SEO-Friendly & Accessible: Semantic HTML, ARIA labels, and schema markup.
Privacy-First: All calculations are done locally — nothing is sent online.

Frequently Asked Questions

Common questions about temperature scales and conversion

What is the difference between Celsius and Fahrenheit?

Celsius (°C) sets water's freezing point at 0° and boiling point at 100°. Fahrenheit (°F) sets these at 32° and 212° respectively. Celsius is used in almost every country; Fahrenheit is primarily used in the United States. They intersect at −40° (i.e. −40 °C = −40 °F).

What is absolute zero?

Absolute zero is the lowest possible temperature, where particles have minimum thermal motion. It equals 0 K, 0 °R, −273.15 °C, or −459.67 °F. It is a theoretical limit — nothing in the universe has ever been cooled to exactly absolute zero, though laboratories have come extremely close.

Why is Kelvin used in science instead of Celsius?

Kelvin starts at absolute zero, making it an absolute scale with no negative values. This is essential for thermodynamic equations (like the ideal gas law) where proportional relationships between temperature values must hold. In many scientific formulas, using Celsius or Fahrenheit would give incorrect results because they use arbitrary zero points.

What is the Rankine scale used for?

The Rankine scale is an absolute temperature scale that uses Fahrenheit-sized degrees. It is mainly used in some areas of engineering in the United States, especially in thermodynamics and heat transfer calculations where engineers are already working in Fahrenheit. Like Kelvin, Rankine starts at absolute zero (0 °R).

Is this converter accurate?

Yes. All conversions use the internationally recognised formulas with up to 10 significant figures of precision. Results are rounded to 4 decimal places for readability. The converter uses JavaScript's native floating-point arithmetic, which is accurate for all practical purposes.

Can I use this converter offline?

All conversion logic runs entirely in your browser. Once the page is loaded, you can use it without an internet connection. No data is ever sent to a server, and your input values remain completely private.

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