Convert Degree to Radian

Simple, fast and user-friendly online tool to convert Degree to Radian ( ° to rad ) vice-versa and other Angle related units. Learn and share how to convert Degree to Radian ( ° to rad ). Click to expand short unit definition.

Please select a valid country.
Clear input
   Degree (°) =    Radian (rad)

What is Degree ?

A Degree is a unit of measurement used to describe the size of an angle. It’s one of the most common ways to measure angles and is widely used in everyday life, mathematics, engineering, and many other fields.

Understanding a Degree

Imagine a circle. A full circle is divided into 360 equal parts. Each one of these parts is called a degree and is denoted by the symbol °. So, if you were to start at one point on the circle and go all the way around back to that point, you would have turned through 360 degrees (360°).

Visualizing Degrees
  • 90°: This is called a right angle and looks like the corner of a square or rectangle. It represents one-quarter of a full circle.
  • 180°: This is called a straight angle and forms a straight line. It’s half of a full circle.
  • 360°: This is a full angle or a complete circle. It’s like doing a full turn and coming back to your starting point.
Key Types of Angles Measured in Degrees
  • Acute Angle: Less than 90°, like the sharp angles in a triangle.
  • Right Angle: Exactly 90°, forming a perfect “L” shape.
  • Obtuse Angle: More than 90° but less than 180°, like the wide angles you might see in an open door.
  • Straight Angle: Exactly 180°, forming a straight line.
  • Reflex Angle: More than 180° but less than 360°, like the angle you get when you keep turning past a straight line.
Why 360 Degrees?

The number 360 is used because it has many divisors, making it easy to work with fractions of a circle. For example:

  • 360° can be divided by 2 (180°), by 3 (120°), by 4 (90°), by 6 (60°), and so on.
  • This makes it convenient for dividing a circle into equal parts, such as in geometric constructions or for clock faces.
Tools for Measuring Degrees
  • Protractor: A tool marked in degrees from 0° to 180°, used to measure or draw angles.
  • Compass: Used to draw circles and can help measure degrees when combined with a protractor.
  • Scientific Calculator: Often used in math and science to calculate angles in degrees, especially when converting between other units like radians.
Everyday Examples of Degrees
  • Clock: The hour hand moves 30° for every hour (since 360°/12 hours = 30°).
  • Navigation: Directions are often given in degrees. For example, North is 0°, East is 90°, South is 180°, and West is 270°.
Summary
  • A degree is a unit of measurement for angles, with a full circle equal to 360°.
  • Degrees are easy to understand and widely used in various fields.
  • They help describe how much something turns or rotates, whether it’s a simple angle in geometry or the direction of a compass.

Understanding degrees is fundamental to geometry and helps us describe the world around us in terms of direction, rotation, and shapes.




What is Radian ?

A Radian is a unit of measurement used to describe the size of an angle. It’s particularly important in mathematics, especially in trigonometry and calculus, because it directly relates angles to the geometry of a circle.

Understanding a Radian

Imagine a circle with a center and a radius, which is the distance from the center of the circle to any point on its edge. A radian measures an angle by looking at the length of the arc (a part of the circle’s edge) that the angle creates, compared to the radius of the circle.

How a Radian is Defined

A radian is defined as the angle created when the length of the arc is exactly equal to the radius of the circle. Here’s how to picture it:

  • Take a circle.
  • Draw a radius (a straight line from the center to the edge).
  • Now, imagine a point on the edge of the circle.
  • If you move this point along the edge so that the distance it travels (the arc length) is exactly the same as the radius, the angle formed between the two radii is 1 radian.
Key Facts About Radians
  • Full Circle in Radians:

    • A full circle is 2π radians because the circumference of a circle (which is the full length around it) is 2π times the radius.
    • This means that 360° (degrees) is equal to 2π radians.
  • Conversions Between Degrees and Radians:

    • To convert from degrees to radians, multiply by π/180. For example, 180° is π radians.
    • To convert from radians to degrees, multiply by 180/π. So 1 radian is approximately 57.3°.
  • Common Radian Values:

    • π/6 radians = 30°
    • π/4 radians = 45°
    • π/3 radians = 60°
    • π/2 radians = 90° (a right angle)
    • π radians = 180° (a straight angle)
Why Use Radians?

Radians are especially useful in higher mathematics because they make the relationship between angles and other parts of a circle more straightforward. For example:

  • In trigonometry, the sine, cosine, and tangent functions naturally work with radians.
  • In calculus, when you differentiate or integrate trigonometric functions, using radians simplifies the math.
Everyday Examples of Radians

While degrees are more commonly used in everyday life, radians are essential in fields like physics, engineering, and computer graphics, where precise mathematical relationships are needed.

Summary
  • A radian is a unit of angle measurement that directly relates the angle to the radius of a circle.
  • 1 radian is the angle formed when the arc length equals the radius of the circle.
  • Radians are especially useful in mathematics, making it easier to work with angles in trigonometry and calculus.
  • A full circle is 2π radians, which equals 360 degrees.

Understanding radians is key to mastering advanced mathematical concepts, and it’s a fundamental unit of measurement in various scientific and engineering fields.



List of Angle conversion units
Degree Radian Milliradian Microradian Gradian Revolution Arc minute Arc second Milliarcsecond Microarcsecond