How to use the normal incidence reflectance calculator
Find the fraction of light reflected and transmitted at a flat boundary between two media. Enter index of first medium, index of second medium in the fields above; the reflectance, transmittance are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “glass reflection percentage”, “reflectance”, “Fresnel normal incidence”, “calculate normal incidence reflectance”, “find reflectance”.
Formula
Variables
- n1 — Index of first medium
- n2 — Index of second medium
Worked example
With index of first medium = 1, index of second medium = 1.5, the calculator gives reflectance ≈ 4 %; transmittance ≈ 96 %.
Frequently asked questions
What is the normal incidence reflectance calculator used for?
Find the fraction of light reflected and transmitted at a flat boundary between two media. It helps with questions such as “glass reflection percentage”, “reflectance”, “Fresnel normal incidence”.
What is the formula for the normal incidence reflectance calculation?
Reflectance (%) = ((n1-n2) / (n1+n2))^2 × 100. Transmittance (%) = 100-[Reflectance]. Here n1 is index of first medium, n2 is index of second medium.
What inputs do I need for the normal incidence reflectance calculator?
You need index of first medium, index of second medium. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the normal incidence reflectance calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the normal incidence reflectance result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.