Convert Radians (rad) to Arc Seconds (")

1 radian equals 206265 arc seconds.

Formula: " = rad × 206265

Radian to Arc Second Converter

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How to Convert Radian to Arc Second

1 radian = 206265 arc seconds

Arc Second = Radian × 206265

Example: 1 rad × 206265 = 206265"

Reverse Conversion

To convert arc seconds back to radians:

  • Remember, 1 arc second equals 4.84814 × 10-6 radians.
  • To convert 206265" to rad, multiply 206265 x 4.84814 × 10-6, resulting in 1 rad.

Common Radian to Arc Second Conversions

Radian to Arc Second (Part 1)
Radian to Arc Second common conversions part 1
Radian Arc Second Actions
1 radian 206265 arc seconds
5 radians 1031320 arc seconds
10 radians 2062650 arc seconds
25 radians 5156620 arc seconds
Radian to Arc Second (Part 2)
Radian to Arc Second common conversions part 2
Radian Arc Second Actions
50 radians 1.03132 × 107 arc seconds
100 radians 2.06265 × 107 arc seconds
500 radians 1.03132 × 108 arc seconds
1000 radians 2.06265 × 108 arc seconds

Radians to arc seconds Conversion Table

Reference table with common radians to arc seconds conversions. All values calculated with high precision.

Radians to Arc Seconds Table
0.0001 to 12

Radians Arc seconds Actions
0.0001 rad 20.6265 "
0.00025 rad 51.5662 "
0.0005 rad 103.132 "
0.001 rad 206.265 "
0.0025 rad 515.662 "
0.005 rad 1031.32 "
0.01 rad 2062.65 "
0.025 rad 5156.62 "
0.05 rad 10313.2 "
0.1 rad 20626.5 "
14 rad 51566.2 "
12 rad 103132 "

Radians to Arc Seconds Table
1 to 100000

Radians Arc seconds Actions
1 rad 206265 "
12 rad 515662 "
5 rad 1031320 "
10 rad 2062650 "
25 rad 5156620 "
50 rad 1.03132 × 107 "
100 rad 2.06265 × 107 "
250 rad 5.15662 × 107 "
500 rad 1.03132 × 108 "
1000 rad 2.06265 × 108 "
2500 rad 5.15662 × 108 "
5000 rad 1.03132 × 109 "
10000 rad 2.06265 × 109 "
25000 rad 5.15662 × 109 "
50000 rad 1.03132 × 1010 "
100000 rad 2.06265 × 1010 "

Arc Seconds to Radians Table
100 to 500000

Arc seconds Radians Actions
100 " 0.000484814 rad
250 " 0.00121203 rad
500 " 0.00242407 rad
1000 " 0.00484814 rad
2500 " 0.0121203 rad
5000 " 0.0242407 rad
10000 " 0.0484814 rad
25000 " 0.121203 rad
50000 " 0.242407 rad
100000 " 0.484814 rad
250000 " 1.21203 rad
500000 " 2.42407 rad

Arc Seconds to Radians Table
1000000 to 1 × 1011

Arc seconds Radians Actions
1000000 " 4.84814 rad
2500000 " 12.1203 rad
5000000 " 24.2407 rad
10000000 " 48.4814 rad
2.5 × 107 " 121.203 rad
5 × 107 " 242.407 rad
1 × 108 " 484.814 rad
2.5 × 108 " 1212.03 rad
5 × 108 " 2424.07 rad
1 × 109 " 4848.14 rad
2.5 × 109 " 12120.3 rad
5 × 109 " 24240.7 rad
1 × 1010 " 48481.4 rad
2.5 × 1010 " 121203 rad
5 × 1010 " 242407 rad
1 × 1011 " 484814 rad

Definition of Radian

Definition

The radian (rad) is the SI derived unit of plane angle. It is defined as the angle subtended at the center of a circle by an arc equal in length to the radius.

Although mathematically dimensionless, the radian is retained as a named unit in the SI to preserve clarity in scientific, engineering, physics, trigonometry, and calculus contexts.

Exact factor
Base unit: 1 rad = 1 rad; full circle: 2π rad = 360°
Examples
  • π rad = 180°
  • 1 rad ≈ 57.2958°
  • 2π rad = 1 turn

About the Radian

Facts & Uses

  • SI coherent unit of plane angle: 1 rad = the angle subtended at a circle's center by an arc equal in length to the radius. 1 full circle = 2π rad ≈ 6.283 rad.
  • Universal in mathematics, physics, engineering, and computer graphics — wherever calculus or trigonometric derivatives are involved.
  • Standard for angular velocity (rad/s), angular acceleration (rad/s²), and phase angles in electrical engineering and signal processing.
  • Common reference: π/6 rad = 30°, π/4 = 45°, π/3 = 60°, π/2 = 90°, π = 180°, 2π = 360°.

Curiosities

  • The radian was first proposed by Roger Cotes in 1714, but the name "radian" wasn't coined until 1873 by James Thomson (brother of Lord Kelvin).
  • Programming functions like Math.sin() and Math.cos() in JavaScript, Python, C, and most languages take radians as input — a frequent source of bugs for developers expecting degrees.
  • The reason calculus prefers radians: the derivative of sin(x) is cos(x) only when x is in radians. With degrees, you'd need a π/180 factor everywhere.
  • Approximate equivalents: 1 rad ≈ 57.2958° ≈ 63.66 grad ≈ 3437.75 arcminutes.

Sources

Frequently Asked Questions

How many arc seconds are in one radian?

One radian equals 206265 arc seconds. To convert, multiply the radian value by 206265. For the reverse, divide the arc second value by 206265 (or multiply by 4.84814 × 10-6).

What is 100 radians in arc seconds?

100 radians = 2.0626 × 107 arc seconds. This is one of the most commonly searched conversions for this pair.

How precise is the radian-to-arc second conversion?

The factor 206265 is accurate to 6 significant figures, derived from international measurement standards. Our calculator uses full precision internally.

Looking for the reverse? Convert Arc Second to Radian

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Conversion factors verified against BIPM, ISO 80000-3 1 turn = 2π rad = 360° (exact, ISO 80000-3). Last reviewed: March 2026
Tiago Fernandes Reviewed by Tiago Fernandes

All unit conversions on CoolConversion use conversion factors defined or documented by internationally recognised standards bodies (such as ISO and NIST), including both SI and non-SI units.