Optics
Lens Formula Calculator
Thin lens equation (1/f = 1/v − 1/u): solve for focal length, object or image distance, with magnification.
1/f = 1/v + 1/u
Also called thin lens equation · image distance calculator
Science · 8 calculators
Optics Calculators
Thin lens and mirror equations, magnification, focal length, lens power, refractive index, Snell's law and critical angle.
Optics
Magnification Calculator
Magnification from image and object size or distances, for lenses, mirrors and microscopes.
m = h_image / h_object = −v/u
Also called magnification formula · image size calculator
Optics
Focal Length Calculator
Focal length from object and image distances, from lens power, or from the lensmaker's equation.
1/f = 1/u + 1/v
Also called focal length formula · lensmaker equation
Optics
Mirror Equation Calculator
Curved mirror equation (1/f = 1/v + 1/u) with radius of curvature, image position and magnification.
1/f = 1/v + 1/u, f = R/2
Also called concave mirror calculator · convex mirror
Optics
Refractive Index Calculator
Refractive index from the speed of light in a medium, or from angles of incidence and refraction.
n = c / v
Also called index of refraction · n = c/v
Optics
Snell's Law Calculator
Angle of refraction when light passes between two media, with total internal reflection detection.
n₁ sin θ₁ = n₂ sin θ₂
Also called refraction calculator · angle of refraction
Optics
Critical Angle Calculator
Critical angle for total internal reflection between two media — the basis of optical fibres.
θ_c = arcsin(n₂ / n₁)
Also called total internal reflection · tir calculator
Optics
Lens Power Calculator
Lens power in diopters from focal length (and back), plus the combined power of two lenses.
P (diopters) = 1 / f (metres)
Also called diopter calculator · glasses prescription power
Key optics formulas
| Lens Formula | 1/f = 1/v + 1/u · m = −v/u |
|---|---|
| Magnification | m = h_image / h_object = −v/u |
| Focal Length | 1/f = 1/u + 1/v · P = 1/f(m) · Lensmaker: 1/f = (n−1)(1/R₁ − 1/R₂) |
| Mirror Equation | 1/f = 1/v + 1/u, f = R/2 |
| Refractive Index | n = c / v · n₁sin θ₁ = n₂sin θ₂ |
| Snell's Law | n₁ sin θ₁ = n₂ sin θ₂ |
| Critical Angle | θ_c = arcsin(n₂ / n₁) |
| Lens Power | P (diopters) = 1 / f (metres) |