GeometryFree

Hexagon Side Calculator

Hexagon side calculator finds the side length of a regular hexagon from its area or perimeter. Area 64.95 gives side 5. Perimeter 30 gives side 5. Reverse-engineers hexagon dimensions from known measurements.

Enter Values

Area (optional)

Perimeter (optional)

Result

Enter values above and click Calculate to see your result.

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Formula

Core Formula

s = \sqrt{\frac{2A}{3\sqrt{3}}} \quad \text{or} \quad s = \frac{P}{6}

How it works: From area: rearrange A = (3sqrt(3)/2)s^2 to solve for s. From perimeter: divide by 6 since a regular hexagon has 6 equal sides.

Worked Example

Find the side length of a hexagon with area 64.95.

1Step 1: s = sqrt(2A / (3sqrt(3))) = sqrt(2 x 64.95 / (3 x 1.7321)).

2Step 2: = sqrt(129.9 / 5.1963) = sqrt(25.0) = 5.0. Verify: A = (3sqrt(3)/2) x 25 = 64.95. From perimeter: if P = 30, then s = 30 / 6 = 5. Both methods give the same answer when the hexagon is regular.

Finding Hexagon Side Length from Area or Perimeter

If you know a regular hexagon's area or perimeter, you can reverse-engineer the side length using simple algebra.

From area: s = sqrt(2A / (3sqrt(3))), approximately sqrt(A / 2.5981)
From perimeter: s = P / 6 (a regular hexagon has 6 equal sides)
Once you have the side, apothem = s x sqrt(3)/2 and circumradius = s
Practical use: measure across flats of a hex bolt to find apothem, then s = 2 x apothem / sqrt(3)

This calculator is the reverse of the hexagon area calculator. Use it when you know the area or perimeter and need to find the side length for cutting, manufacturing, or design.

You can also calculate changes using our Hexagon Area Calculator, Octagon Dimensions Calculator or Circle Geometry Theorem Solver.

Frequently Asked Questions

What side length gives a hexagon area of 100?

s = sqrt(2 x 100 / (3 x 1.7321)) = sqrt(200 / 5.1963) = sqrt(38.49) = 6.20. A regular hexagon with side 6.20 has area approximately 100 square units.

How do I find the side from perimeter?

Divide the perimeter by 6. A regular hexagon with perimeter 42 has side = 42 / 6 = 7. This works because all six sides of a regular hexagon are equal.

What if I enter both area and perimeter?

The calculator computes side from both inputs and uses the area-derived value as the primary result. If the hexagon is truly regular, both methods should give the same answer. A discrepancy indicates measurement error or a non-regular hexagon.

How do I convert a hex bolt "across flats" measurement to side length?

The "across flats" dimension of a hex bolt equals 2 x apothem = s x sqrt(3). So side = across-flats / sqrt(3) = across-flats / 1.7321. A 19mm hex bolt has side = 19 / 1.7321 = 10.97 mm.

Is this calculator only for regular hexagons?

Yes. The formulas assume all six sides are equal and all six angles are 120 degrees. Irregular hexagons have no single "side length" and require different methods to analyze.

Is it possible to embed the Hexagon Side Calculator on another website?

Yes, embedding the Hexagon Side Calculator is free. Hit the "Embed" button on this page, adjust the width, height, and theme, then grab the iframe code. It works on WordPress, Wix, Squarespace, Shopify, and plain HTML pages. No registration needed. Full instructions at calculory.com/services/embed-calculators.

AI Assistant

Ask about this calculator

I can help you understand the hexagon side calculator formula, interpret your results, and answer follow-up questions.

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