Hexagon Perimeter Calculator
A regular hexagon has six equal sides and six equal angles, which makes its perimeter just six times the side length. Enter a side length and this calculator returns the perimeter, along with the area, the long diagonal (between opposite vertices) and the short diagonal. Hexagons tile a plane perfectly, which is why they appear in honeycomb, bolt heads and tiling patterns, and the formulas here are exact geometric results that need no measured constant. Use consistent units throughout.
Hexagon formulas
Perimeter = 6 x side
Area = (3 x square root of 3 / 2) x side squared
Long diagonal = 2 x side
Short diagonal = square root of 3 x side
These come directly from dividing a regular hexagon into six equilateral triangles. The area constant 3 x root 3 / 2 is approximately 2.598, an exact value with no estimation.
Hexagon geometry context
- A regular hexagon has six equal sides and interior angles of 120 degrees.
- Regular hexagons tile a flat plane with no gaps, as seen in honeycomb.
- The long diagonal (vertex to opposite vertex) is exactly twice the side.
- The short diagonal equals the side times the square root of 3.
- Use the same length unit for the side and read the outputs in that unit (area in unit squared).
Hexagon perimeter: frequently asked questions
What is the perimeter of a regular hexagon?
A regular hexagon has six equal sides, so its perimeter is simply six times the side length: P = 6s. For a side of 5 units the perimeter is 6 x 5 = 30 units. This calculator also returns the area and the two diagonal lengths for the same side.
How do you find the area of a regular hexagon?
The area of a regular hexagon is (3 x square root of 3 / 2) times the side length squared, which is approximately 2.598 times s squared. The constant comes from dividing the hexagon into six equilateral triangles. This is an exact geometric result, not an estimate.
What are the long and short diagonals of a hexagon?
The long diagonal runs between two opposite vertices and equals twice the side length (2s). The short diagonal runs between two vertices with one between them and equals the side times the square root of 3 (about 1.732s). Both follow directly from the hexagon's geometry.
Does this work for an irregular hexagon?
No. This calculator assumes a regular hexagon, where all six sides and angles are equal. For an irregular hexagon you must add the six individual side lengths to find the perimeter, and the area requires a different method such as dividing it into triangles.
Where do regular hexagons appear?
Regular hexagons tile a plane with no gaps, which is why they appear in honeycomb, bolt heads, floor tiles and many engineering patterns. The efficient packing and equal sides make the simple perimeter and area formulas widely useful in design and construction.
Official sources
- U.S. National Institute of Standards and Technology: Digital Library of Mathematical Functions.
- NASA: Geometry and area reference.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.