radians to arcseconds | Exact Decimal + Formula
One radian equals about 206.3 thousand arcseconds (exactly 206264.8062 arcsec). Real-world use: calculus, physics, and programming trigonometry functions. This page expresses those values in arcseconds, which is used for astronomical measurements of star positions and telescope resolution. Type a value above for an instant answer; the exact formula and the reference table are below.
About Radian and Arcsecond
Radian (rad)
A radian is the angle subtended by an arc equal to the circle's radius; a full circle is 2π radians.
Where it's used: Calculus, physics, and programming trigonometry functions.
Arcsecond (arcsec)
An arcsecond is 1/3,600 of a degree.
Where it's used: Astronomical measurements of star positions and telescope resolution.
Angle Converter
Formula
arcsec = rad × 206264.806247096
To convert Radian to Arcsecond, use the formula displayed above.
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Radian to Arcsecond: Quick Reference Table
| Radian | Arcsecond (Decimal) | Fraction |
|---|---|---|
| 0.001 rad | 206.264806 arcsec | - |
| 0.01 rad | 2062.648062 arcsec | - |
| 0.1 rad | 20626.480625 arcsec | - |
| 0.5 rad | 103132.403124 arcsec | - |
| 1 rad | 206264.806247 arcsec | - |
| 2 rad | 412529.612494 arcsec | - |
| 5 rad | 1031324.031235 arcsec | - |
| 10 rad | 2062648.062471 arcsec | - |
| 25 rad | 5156620.156177 arcsec | - |
| 50 rad | 10313240.312355 arcsec | - |
| 100 rad | 20626480.62471 arcsec | - |
| 250 rad | 51566201.561774 arcsec | - |
| 500 rad | 103132403.123548 arcsec | - |
| 1000 rad | 206264806.247096 arcsec | - |
rad to arcsec Formula and Examples
arcsec = rad × 206264.806247096 rad = arcsec × 0.000005 Multiply the value by roughly 206264.8 to calculate the equivalent amount in your head.
Common Radian to Arcsecond Calculations
- 5 rad = 1031324.031235 arcsec
- 10 rad = 2062648.062471 arcsec
- 50 rad = 10313240.312355 arcsec
- 100 rad = 20626480.62471 arcsec
- 500 rad = 103132403.123548 arcsec
Precision & Practical Use
For example, 10 rad = 2062648.062471 arcsec — roughly multiple unit increments.
Results are computed to up to 9 decimal places. Round to the precision of your measuring instrument — for most angle applications, 2–3 significant figures are plenty.