What is the formula for the perimeter of a regular heptagon?

The perimeter of a regular heptagon is P = 7s, where s is the length of one side. Because all seven sides are equal in a regular heptagon, you simply multiply the side length by 7.

Does this calculator work for irregular heptagons?

No. This tool is designed for regular heptagons only, where all seven sides are equal. For an irregular heptagon, you would need to add up all seven individual side lengths.

What units can I use?

You can enter measurements in millimeters (mm), centimeters (cm), meters (m), inches (in), feet (ft), or yards (yd). The result is shown in the same unit you select.

What is the difference between the perimeter and the area of a heptagon?

Perimeter is the total length of the outer boundary (P = 7s), while area is the space enclosed inside the shape. The area formula for a regular heptagon is A = (7/4) * s^2 * cot(pi/7). This tool calculates perimeter only.

Can I use decimal values for the side length?

Yes. Decimal side lengths are fully supported. For example, entering 3.5 cm gives a perimeter of 24.5 cm.

What are the interior angles of a regular heptagon?

Each interior angle of a regular heptagon measures (7-2) x 180 / 7 = 900 / 7 ≈ 128.57 degrees. All seven angles are equal in a regular heptagon.

Perimeter of a Heptagon Calculator

Enter the side length of a regular heptagon and instantly get its perimeter using P = 7s.

Enter Side Length

Side Length (s)

Formula

P = 7 × s

where s is the side length

Result

Perimeter (P = 7s)

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Summary

A regular heptagon has seven equal sides and seven equal interior angles of approximately 128.57 degrees each. Its perimeter is simply seven times the side length (P = 7s). This calculator accepts any positive side length and common units of measurement, then displays the perimeter instantly along with a visual diagram of the heptagon.

How it works

Enter the side length of your regular heptagon.
Select the unit of measurement (mm, cm, m, in, ft, or yd).
The calculator applies the formula P = 7s to compute the perimeter.
Results are displayed instantly with the chosen unit.
A breakdown shows the side length, number of sides, and final perimeter.
Use the copy button to copy the result to your clipboard.

Use cases

Calculate the total border length for a heptagonal decorative frame or mirror.
Determine fencing material needed for a seven-sided garden bed.
Solve geometry homework problems involving regular heptagons.
Find the perimeter of heptagonal architectural or flooring elements.
Verify manual calculations for engineering or design projects.
Compute trim lengths for heptagonal crafting and woodworking projects.
Estimate material costs for seven-sided tile borders or inlays.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu