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Short answer
Area is the surface inside a shape (square units); perimeter is the distance around it (linear units). Shapes with a 12 m perimeter can enclose 5, 8, 9 or 11.46 m², so you cannot get one from the other.
1. The difference
| Area | Perimeter | |
|---|---|---|
| Measures | Surface inside | Distance around |
| Units | m², ft² | m, ft |
| Rectangle | l × w | 2(l + w) |
| Used for | Flooring, paint, land | Fencing, trim, borders |
2. Same perimeter, different area
| Shape (12 m perimeter) | Area |
|---|---|
| Rectangle 5 × 1 | 5 m² |
| Rectangle 4 × 2 | 8 m² |
| Square 3 × 3 | 9 m² |
| Circle, r ≈ 1.91 | 11.46 m² |
For a fixed perimeter, the circle encloses the most area.
The Area Calculator shows both the area and perimeter of every shape.
3. Frequently asked questions
What is the difference between area and perimeter?expand_more
Area is the space inside a shape in square units. Perimeter is the length of its boundary.
Can I find area from perimeter?expand_more
No. A 12 m perimeter can enclose 5, 8, 9 or 11.46 m² depending on the shape.
Which shape has the most area for a given perimeter?expand_more
The circle.
Which do I need for flooring or a fence?expand_more
Area for flooring, perimeter for a fence.