Angle of Incidence Calculator
Calculate the angle of incidence using Snell's Law given refractive indices and angle of refraction. Includes Fresnel reflectance and Brewster angle.
Free Optics Calculators
21 toolsLens, mirror, refraction, diffraction, and light intensity calculators. Browse our free optics tools below — no sign-up required.
Angle of Refraction Calculator
Calculate the angle of refraction using Snell's Law. Includes critical angle, Brewster angle, Fresnel reflectance, and a multi-angle comparison table.
Angular Resolution Calculator
Calculate angular resolution using the Rayleigh criterion, Dawes' limit, and Sparrow limit. Compare apertures and find minimum resolvable features.
Aperture Area Calculator
Calculate the area of circular apertures for telescopes, cameras, and optical systems. Compare f-stops, central obstruction, and light gathering power.
Brewster Angle Calculator
Calculate Brewster's angle for any two media. Includes polarization reflectance, angle comparison tables, and material reference data.
Contact Lens Vertex Distance Calculator
Convert spectacle prescription to contact lens power using vertex distance compensation. Handles sphere, cylinder, and rounding to 0.25 D steps.
Diffraction Calculator
Calculate diffraction patterns for single slit, double slit, diffraction grating, and circular aperture. Includes angle, fringe spacing, and order tables.
Hair Diffraction Calculator
Measure hair diameter using laser diffraction (Babinet's principle). Calculate fringe positions, pattern width, and classify hair type from diffraction data.
Index of Refraction Calculator
Calculate the refractive index from speed of light or Snell's Law angles. Includes material comparison, Brewster angle, critical angle, and wavelength data.
Laser Beam Divergence Calculator
Calculate laser beam divergence, spot size at distance, Rayleigh range, and far-field onset. Supports M² beam quality factor and distance tables.
Laser Beam Expander Calculator
Design Galilean and Keplerian beam expanders. Calculate output beam size, divergence reduction, lens focal lengths, and Rayleigh range improvement.
Laser Brightness Calculator
Calculate laser radiance (brightness), spectral radiance, intensity, beam parameter product, and M² factor. Supports CW and pulsed modes.
Laser Linewidth Calculator
Convert laser linewidth between frequency, wavelength, and wavenumber. Calculate coherence length, coherence time, quality factor, and cavity modes.
Laser Spot Size Calculator
Calculate focused laser spot size, depth of focus, intensity, and power density. Compare focal lengths and evaluate cutting/welding parameters.
Lensmaker's Equation Calculator
Use the lensmaker's equation to find focal length, optical power, and image distance from lens curvature, refractive index, and thickness.
Lumen Calculator
Convert between lumens, candela, lux, and foot-candles. Calculate luminous efficacy, illuminance at distance, and compare light sources.
Lux to Foot-Candle Calculator
Convert between lux and foot-candles. Calculate total lumens for an area, luminous exitance, and compare illuminance levels for different environments.
Mirror Equation Calculator
Calculate image distance, magnification, and image properties for concave and convex mirrors using the mirror equation 1/f = 1/d_o + 1/d_i.
Snell's Law Calculator
Apply Snell's law to find refraction angle, critical angle, Brewster's angle, and Fresnel reflectance at any optical interface.
Telescope Magnification Calculator
Calculate telescope magnification, exit pupil, true field of view, resolution limits, and light gathering power. Compare eyepieces and Barlow lenses.
Thin Lens Equation Calculator
Solve the thin lens equation 1/f = 1/d_o + 1/d_i for image distance, magnification, and image characteristics. Supports converging and diverging lenses.