Fresnel Reflectance Calculator
Calculate s, p and unpolarized power reflectance at one lossless dielectric interface.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Apply Snell’s law and the dielectric Fresnel power coefficients; handle total internal reflection separately.
Rs=[(n1 cosθ1−n2 cosθ2)/(n1 cosθ1+n2 cosθ2)]²; Rp uses exchanged n factors
Worked example
At normal incidence from n=1 to n=1.5, both polarizations reflect 4% and transmit 96%. At the Brewster angle, ideal p reflectance vanishes.
Assumptions and input details
Positive real indices, nonmagnetic lossless media and one planar boundary. Power transmission is 1−R under these assumptions; no complex absorbing index, multilayer coating, phase or roughness model. Total internal reflection omits the evanescent-wave phase.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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