Fresnel Equations Calculator
Compute reflectance and transmittance at a flat interface (normal incidence).
Input Data
N1
N2
Results
R = ((n₁−n₂)/(n₁+n₂))².
0.04
R in percent.
4%
T = 1 − R.
0.96
Critical angle if n₁>n₂.
0°
At a glance:R = ((n₁−n₂)/(n₁+n₂))²; T = 1−R (normal incidence). Complements critical-angle and refractive-index.
Formula
R = ((n₁−n₂)/(n₁+n₂))².
$$R = \left(\frac{n_1 - n_2}{n_1 + n_2}\right)^2, \quad T = 1 - R, \quad \theta_c = \arcsin\frac{n_2}{n_1}$$How to Use
- Enter n₁ and n₂.
- The tool returns R, T and critical angle.
Case Studies
air→glass n₁=1, n₂=1.5
R = 0.04 (4%).
FAQ
Oblique incidence?
Use the full Fresnel s/p formulas with the angle.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.