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Pentagon area calculator

Compute the area of a regular pentagon from its side length.

Related tools

All Geometry tools →
Hexagon area calculatorCompute the area of a regular hexagon from its side length.Regular polygon area calculatorCompute the area of a regular polygon from its number of sides and side length.Triangle area calculator (Heron's formula)Compute a triangle's area from the length of its three sides.Trapezoid area calculatorCompute the area of a trapezoid from its two parallel sides and height.Area calculatorCompute the area of a rectangle, square, circle or triangle.Circle sector area calculatorCompute the area and arc length of a circle sector from its radius and angle.Annulus (ring) area calculatorCompute the area of a ring from its outer and inner radius.Cone surface area calculatorCompute the total surface area and slant height of a cone from its radius and height.

Enter Side length and the Pentagon area calculator works out Area straight away. For instance, with Side length = 10 it returns Area = 172.048.

How to use it

  1. Enter your values: Side length.
  2. Read the result instantly: Area.

Frequently asked questions

What does the Pentagon area calculator actually compute?

It takes Side length and derives Area from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

A single value: Side length. Nothing else is required — no account, no file upload.

Can you show a worked example?

With Side length = 10, the calculator returns Area = 172.048. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

What happens if I enter larger values?

It moves a lot. Using Side length = 20 instead, Area goes from 172.048 to 688.191 — which is why it is worth testing a few scenarios rather than trusting a single figure.

What does it give for smaller values?

Scaled down to Side length = 5, Area comes out at 43.012. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Homework and site work alike: how much paint a wall takes, how much water a tank holds, whether a corner is square — and, on the coordinate side, the slope between two points, the distance across a plan, the midpoint of a span.

What is the most common mistake?

Mixing units inside one shape. Entering a length in centimetres and a width in metres gives an area wrong by a factor of a hundred, and the result looks perfectly plausible.

Is there a tool for the next step?

Regular polygon area calculator is the closest one after this: Compute the area of a regular polygon from its number of sides and side length.

What else is worth having open alongside it?

Triangle area calculator (Heron's formula) and Trapezoid area calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from, and how current are they?

The formulas are the classical ones and the results are exact to the precision shown — geometry does not change with the year or the country, so nothing here needs updating.

Further reading

All guides →
How-toCircle: Circumference and AreaCircumference is 2πr, area is πr². Here's how radius, diameter and π fit together, both formulas worked through, and how not to mix them up.How-toHow to Find the Area of a Triangle: Base × Height and Heron's FormulaTwo reliable ways to find a triangle's area: half base times height when you know the height, and Heron's formula when you only know the three sides.ExplainerThe Pythagorean Theorem ExplainedIn a right triangle, a² + b² = c². Here's what the formula means, a worked example, how to find any side, and where it's used in real life.How-toHow to Calculate VolumeVolume is the space inside a shape. Here's how to find it for boxes, cylinders and spheres, and why keeping your units consistent is the whole game.How-toHow to Calculate the Square Metres of a RoomFind a room's area by multiplying length by width. Here's the method for rectangular, L-shaped and round rooms, and why area drives your material orders.How-toHow Many Tiles Do You Need? (Floor and Wall)Estimate tiles from the area to cover and one tile's size, then add for cuts and waste. Here's the method, with an example and the 10% rule.