Perimeter of a Rectangle Calculator
⬛ Area & perimeter (2D). Use the Perimeter of a rectangle formula to find perimeter, length, width: pick the value you want, type the others, and the answer updates as you go.
Perimeter20 cm
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Perimeter | cm |
| Length | cm |
| Width | cm |
Worked example
Find the perimeter when Length = 6 cm, Width = 4 cm.
Using P = 2(l + w): Perimeter = 20 cm.
Frequently asked questions
What is the formula for Perimeter of a rectangle?
P = 2(l + w).
What do the letters stand for, and what units are used?
Perimeter in cm, Length in cm, Width in cm.
How do you calculate perimeter?
Put the values into P = 2(l + w). For example, with Length = 6 cm, Width = 4 cm, perimeter = 20 cm.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (perimeter, length, width) and fill in the others: it rearranges the formula for you.
