How do I convert Fahrenheit to Celsius?

°C = (°F - 32) × 5/9. For example, 98.6°F = (98.6 - 32) × 5/9 = 37°C.

How many meters in a mile?

1 mile = 1,609.344 meters exactly.

How do I convert kg to pounds?

1 kg = 2.20462 lbs. Multiply kg by 2.20462 to get pounds.

Unit Converter — 250+ Categories

Constant	Symbol	Value	Units
Speed of light	c	2.99792458×10⁸	m/s
Planck's constant	h	6.62607015×10⁻³‴	J·s
Boltzmann constant	kʙ	1.380649×10⁻²³	J/K
Avogadro's number	Nₐ	6.02214076×10²³	mol⁻¹
Gravitational constant	G	6.6743×10⁻¹¹	N·m²/kg²
Gas constant	R	8.31446	J/(mol·K)
Elementary charge	e	1.602176634×10⁻¹⁹	C
Electron mass	mₑ	9.1093837015×10⁻³¹	kg
Proton mass	mₚ	1.67262192369×10⁻²⁷	kg
Fine-structure constant	α	7.2973525693×10⁻³	dimensionless

Constant

Symbol

Value

Speed of light

2.99792458×10⁸

Planck's constant

6.62607015×10⁻³‴

Boltzmann constant

kʙ

1.380649×10⁻²³

Avogadro's number

Nₐ

6.02214076×10²³

Gravitational constant

6.6743×10⁻¹¹

Gas constant

8.31446

Elementary charge

1.602176634×10⁻¹⁹

Electron mass

mₑ

9.1093837015×10⁻³¹

Proton mass

mₚ

1.67262192369×10⁻²⁷

Fine-structure constant

7.2973525693×10⁻³

Formula Definitions

The Unit Converter — 250+ Categories works by applying a well-defined formula to the values you enter. Understanding the formula behind the calculation helps you interpret the result and check that your inputs are correct. Below we break down the key components that drive the Unit Converter.

The core formula used by this calculator is:

Result = f(inputs, operation)

Each variable in the formula has a specific meaning:

inputs — Numerical values, expressions, or parameters entered into the Unit Converter.
operation — Mathematical operation, formula variant, or method applied to the inputs.
Result — Computed numerical or symbolic output.

Note: Verify results using an alternative method or step-by-step working where available.

How to Use This Calculator

Enter the required values. Enter the required values into the Unit Converter — 250+ Categories input fields.

Adjust settings. Adjust any settings, select applicable options, or choose units as needed.

Calculate the result. Press Calculate to compute the result using the underlying formula.

Interpret the output. Review and interpret your result using the provided context, reference ranges, or explanatory notes.

Glossary and Definitions

Operand

A value or expression on which a mathematical operation is performed.

Operator

A symbol (such as +, ×, ∫) that specifies the operation applied to operands.

Significant digits

The digits of a result that are meaningful given the precision of the inputs.

Closed form

An expression that can be evaluated in a finite number of standard operations.

Unit converter