Octagon Area Calculator (A ≈ 4.8284s²)
This calculator computes the octagon area: exact formula A ≈ 4.8284s², worked example s = 4 cm → A = 77.25 cm², P = 32 cm.
- Free, instant, any units.
Figures are estimates from this calculator’s standard formula — adjust the inputs in the tool below for your exact number.
How the octagon area Calculator Works
The calculator applies the exact formula A = 2(1 + √2)·s² ≈ 4.8284·s². Worked example: s = 4 cm → A = 77.25 cm², P = 32 cm. Keep every input in one unit system and the result follows in square units (m², ft², cm²); full precision is kept until the final rounding. All side lengths must share one unit or the area comes out scaled wrongly.
- 1
Enter the measurements
Type the values required by the formula for octagon area.
- 2
Check the units
One unit system throughout — cm, m, ft or in.
- 3
Read the result
The calculator substitutes, evaluates and rounds only at the end.
Use Cases
Floor, plot and panel measurements
School geometry and land surveying
Double-checking material orders and quotes
Tips
- 1
Area scales with the square of linear dimensions
- 2
1 m² = 10.764 ft² for quick conversion
- 3
Sketch and label the shape before entering values
Common Mistakes
Unit mix-ups between cm² and m² (factor 10,000)
Using a slanted length as a perpendicular height
Treating an irregular shape as regular
FAQs
Related tools
Pick another tool to continue your calculation.
Pentagon Area Calculator (A ≈ 1.7205s²)
Calculate regular pentagon area and perimeter.
Regular Polygon Diagonals Calculator
Calculate diagonals of a regular polygon.
Pyramid Calculator (V = ⅓A·h)
Calculate pyramid volume and surface area.
Pyramid Frustum Volume Calculator
Calculate square pyramid frustum volume.
Square Frustum Calculator (V = h(a²+ab+b²)/3)
Calculate volume of a frustum of pyramid.
Rhombus Area Calculator (A = ½d₁d₂)
Calculate rhombus area and perimeter.