Optics Formulas

A complete list of optics formulas, covering Snell's law, lenses and mirrors, magnification, refraction, diffraction, and the critical angle.

9 formulas. Use the interactive searcher to solve for any variable and convert units.

Snell's law

n₁·sinθ₁ = n₂·sinθ₂

n₁ refractive indexn₂ refractive indexθ₁ angle of incidenceradθ₂ angle of refractionrad

n = c / v

n refractive indexc speed of lightm/sv velocitym/s

1/f = 1/d_o + 1/d_i

f focal lengthmd_o object distancemd_i image distancem

M = −d_i / d_o = h_i / h_o

M magnificationd_i image distancemd_o object distancemh_i image heightmh_o object heightm

sinθ_c = n₂ / n₁

θ_c critical angleradn₁ refractive indexn₂ refractive index

1/f = 1/d_o + 1/d_i

f focal lengthmd_o object distancemd_i image distancem

d·sinθ = m·λ

d slit separationmθ angleradm orderλ wavelengthm

d·sinθ = n·λ

d grating spacingmθ angleradn orderλ wavelengthm

P = 1 / f

P powerWf focal lengthm