Inverse Square Law Calculator

Find how intensity changes with distance.

Intensity at distance 1

Distance 1

Distance 2

Intensity at distance 2 11.111

Formula: I₂ = I₁·(d₁ ÷ d₂)²

Step-by-step with your numbers:

1. Values used:

2. Intensity at distance 1 = 100

3. Distance 1 = 1

4. Distance 2 = 3

6. Intensity at distance 2 = 11.111

Did we solve your problem today?

Many physical quantities spread out, falling off as the inverse square of distance.

The math behind it

I₂ = I₁·(d₁/d₂)². Doubling the distance cuts intensity to a quarter.

100 units at 1 m → about 11.1 units at 3 m.

What follows this law?

Light, sound, gravity and radiation from a point source.