Free · 2D geometry calculators 📏

Regular Polygon Boundary Length and Equal Side

This workflow assumes equal sides. For an irregular polygon, add the actual side lengths instead of multiplying one side by n.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

Example in initial displayed units: Number of sides 6, Side (a) 4 gives Full boundary perimeter 24.

P = na

Worked example

Enter these known values and leave the other values blank.

Number of sides
6
Side (a)
4 cm
Full boundary perimeter
24 cm

Assumptions and limitations

  • A regular polygon has n equal sides, with whole n at least three. Any compatible perimeter and side length can recover n only when their ratio is a whole number at least three. Side lengths and perimeter are positive.
  • Clear unknown measurements before solving backward. Use compatible units and independent values. Reference pictures are original schematic drawings. Independently rounded measurements can fail strict compatibility at a boundary.

Common questions

Does this work for unequal polygon sides?

This workflow assumes equal sides. For an irregular polygon, add the actual side lengths instead of multiplying one side by n.

How do I use this calculator with different units?

Select the unit beside each measure. Length, squared length and volume use different dimensions; changing a unit preserves the physical value. Compound length controls represent feet/inches or meters/centimeters together.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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