Radiation Pressure Calculator

Find the pressure exerted by light on a surface.

Radiation pressure (Pa) 0

Formula: P = I ÷ c (×2 if reflecting)

Step-by-step with your numbers:

1. Values used:

2. Light intensity = 1,361 W/m²

4. Radiation pressure = 0Pa

Did we solve your problem today?

Light carries momentum, so it pushes on surfaces it hits — the basis of solar sails.

The math behind it

P = I/c for an absorbing surface, or 2I/c for a perfect reflector.

Sunlight (1361 W/m²) absorbed → about 4.5 µPa.

Can it move spacecraft?

Yes — solar sails use this tiny but continuous pressure over large areas.