Regular Polygon Calculator (Hexagon, Octagon…)

Regular polygon calculator: area, perimeter, apothem, circumradius and interior angle of a hexagon, octagon or any n-sided regular polygon.

A = n · s²4 · tan(π/n)

How to use this calculator

  1. Choose the quantity you want under “Solve for”.
  2. Type the known values and pick their units: any combination works.
  3. The result updates as you type. Open “Show the steps” to see the substitution.

Area = n s² ÷ (4 tan(π/n)). Each interior angle is (n − 2) × 180° ÷ n: 120° for a hexagon, 135° for an octagon.

Formula

A = n · s²4 · tan(π/n)

SymbolQuantityUnits
nNumber of sides—
sSide lengthm, km, cm, mm, µm, nm, pm, Å, in, ft, yd, mi, nmi, au, ly
AAream², km², cm², mm², ha, ft², in², yd², ac, mi²

Worked example

Given: n = 6 · s = 10 cm

A = n s²4 tan(π/n)

Result: A = 259.808 cm²

Area for different values of Number of sides

n · Number of sidesA · Area
3 43.301 cm²
4.5 134.07 cm²
5.4 205.26 cm²
6 259.81 cm²
6.6 320.06 cm²
7.5 421.13 cm²
9 618.18 cm²
12 1 119.6 cm²

Other values as in the worked example.

Frequently asked questions

Area of a regular hexagon with 10 cm sides?

About 259.8 cm².

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