Solar Flux Calculator

Analyze solar energy intensity across space and surfaces. Model inverse square and projected area effects. Export results quickly with examples, formulas, and practical guidance.

Calculator Inputs

Example Data Table

Scenario Luminosity (W) Distance (AU) Angle (°) Transmittance Area (m²) Approx. Flux (W/m²)
Earth orbit panel 3.828e26 1.00 0 1.00 1.50 1361
Mars orbit surface 3.828e26 1.52 20 0.82 2.00 577
Direct lamp exposure — — 15 0.95 0.50 1900

Formula Used

Base flux from luminosity: F = L / (4πr²)

Base flux from radiant power: F = P / A

Surface adjusted flux: Fadj = F × cos(θ) × τ × (1 − α)

Incident power: Pincident = Fadj × A

Here, L is source luminosity, r is distance, P is radiant power, and A is collector area.

θ is the incidence angle, τ is atmospheric transmittance, and α is reflective loss factor.

The inverse square relation makes flux drop rapidly with distance. Surface tilt and atmosphere further reduce usable energy.

How to Use This Calculator

  1. Choose the calculation method that matches your data source.
  2. Enter luminosity and distance, or radiant power and area.
  3. Add collector area, incident angle, transmittance, and reflective loss factor.
  4. Press Submit to show results above the form.
  5. Use the export buttons to save CSV or PDF output.
  6. Compare the base and adjusted flux to evaluate real exposure conditions.

Notes for Analysis

Use luminosity mode for stars, suns, or radiant celestial sources. Use power mode for lamps, emitters, and local energy systems.

For orbital studies, astronomical units help quickly compare planets. For lab studies, power and area often provide better control.

A surface at 60° receives only half the normal component before other losses. That makes angle control critical in solar design.