18 Arc Seconds to Radians

18" ≈ 8.7266e-5 rad

Calculation: rad = 18" × 4.84814 × 10⁻⁶ ≈ 8.7266e-5 rad

Arc Second to Radian Converter

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Sig. Figures:

How wide is 18"?

18 arc second (0.005 degrees) is comparable to the precision of a telescope crosshair, an almost imperceptible angle.

What does 18" look like?

Illustration of a telescope crosshair reticle
18 arc second (0.005 degrees) is comparable to the precision of a telescope crosshair, an almost imperceptible angle.

How to Convert Arc Second to Radian

1 arc second = 4.84814 × 10-6 radians

Radian = Arc Second × 4.84814 × 10-6

Example: 18" × 4.84814 × 10-6 = 8.7266 × 10-5 rad

Reverse Conversion

To convert radians back to arc seconds:

  • Remember, 1 radian equals 206265 arc seconds.
  • To convert 8.7266 × 10-5 rad to", multiply 8.7266 × 10-5 x 206265, resulting in 18".

18 " is also equal to:

  • 0.005 degree
  • 0.0055556 gradian

Frequently Asked Questions

How much is 18 arc seconds in radians?

18 arc seconds equals 8.7266 × 10⁻⁵ radians. This is calculated by multiplying 18 by the conversion factor 4.84814 × 10⁻⁶.

What does 18 arc seconds look like in radians?

18 arc seconds equals 8.7266 × 10⁻⁵ radians, a conversion used in navigation, trigonometry, and engineering design.

How do you calculate 18 arc seconds to radians?

Multiply 18 by the conversion factor 4.84814 × 10⁻⁶. The calculation is 18 × 4.84814 × 10⁻⁶ = 8.7266 × 10⁻⁵ radians. This factor is defined by international measurement standards.

Share This Calculation

18 arc seconds = 8.72665 × 10⁻⁵ radians
18 arc seconds = 8.72665 × 10⁻⁵ radians — conversion chart

Nearby Conversions

8 arc seconds3.879 × 10⁻⁵ radians 9 arc seconds4.363 × 10⁻⁵ radians 10 arc seconds4.848 × 10⁻⁵ radians 11 arc seconds5.333 × 10⁻⁵ radians 12 arc seconds5.818 × 10⁻⁵ radians 13 arc seconds6.303 × 10⁻⁵ radians 14 arc seconds6.787 × 10⁻⁵ radians 15 arc seconds7.272 × 10⁻⁵ radians 16 arc seconds7.757 × 10⁻⁵ radians 17 arc seconds8.242 × 10⁻⁵ radians 19 arc seconds9.211 × 10⁻⁵ radians 20 arc seconds9.696 × 10⁻⁵ radians 21 arc seconds0.0001018 radians 22 arc seconds0.0001067 radians 23 arc seconds0.0001115 radians 24 arc seconds0.0001164 radians 25 arc seconds0.0001212 radians 26 arc seconds0.0001261 radians 27 arc seconds0.0001309 radians 28 arc seconds0.0001357 radians

For general conversions between arc seconds and radians, see the arc seconds to radians converter.

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