Perimeter of Rectangle Calculator

Calculate rectangle perimeter instantly. Free online rectangle perimeter calculator with length and width.

The Perimeter of Rectangle Calculator computes the total distance around a rectangle using its length and width. Essential for fencing, framing, baseboard installation, and material estimation, this tool applies the formula P = 2(l + w) to give you accurate perimeter measurements. Enter your dimensions and get results instantly.

Common use cases

  • Fence material estimation
  • Baseboard and trim calculations
  • Picture framing
  • Garden edging
  • Athletic field marking

How to use

  1. Enter the length of the rectangle
  2. Enter the width of the rectangle
  3. Click calculate for the perimeter
  4. View the formula: P = 2(l + w)
  5. Copy results for material planning

FAQ

What is the rectangle perimeter formula?

Perimeter = 2 × (length + width) or equivalently 2l + 2w.

Is a square's perimeter calculated the same way?

Yes, for a square where l = w, Perimeter = 4s where s is the side length.

How much fencing do I need?

The perimeter plus extra for posts, gates, and waste—typically add 10-15%.

Can I find dimensions from perimeter?

You need one dimension or the length-to-width ratio plus the perimeter to find both dimensions.