Octagon Calculator
What are the area and perimeter of a octagon? Enter the values below to calculate the result.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Side length (length) | Enter side length in length; use the same basis as the other measurements. |
Understanding your result
Read area (length^2), perimeter (length), interior (degree) in the units and model stated on this page. The formula area=8*s*s/(4*tan(pi/8)) · perimeter=8*s · interior=180*(8-2)/8 defines the relationship; measurement accuracy and model applicability are separate from numerical precision.
Common mistakes
- Mixing input units or changing the physical meaning of a variable without changing the model.
Check your calculation
- Use the worked example as a known reference case, then change one input at a time and check the direction and units of the response.
Calculation checks, sources and review limits
What are the area and perimeter of a octagon?
What are the area and perimeter of a octagon? Enter the values below to calculate the result.
Common uses
- What are the area and perimeter of a octagon
How it works
area=8*s*s/(4*tan(pi/8)); perimeter=8*s; interior=180*(8-2)/8
Worked example
Enter Side length: 2 length. Results: area: 19.31370849898476 length^2; perimeter: 16 length; interior: 135 degree.