Perimeter Calculator

Calculate the perimeter of a shape by selecting a shape and entering your measurements in any unit, metric or imperial. See formulas for each shape below.

Select a Shape:

• Rectangle
• Square
• Trapezoid
• Parallelogram
• Triangle
• Circle
• Ellipse
• Sector
• Polygon

Rectangle Perimeter Calculator

Length:

in ft yd cm m

Width:

in ft yd cm m

HELP

Square Perimeter Calculator

Edge Length:

in ft yd cm m

HELP

Trapezoid Perimeter Calculator

Base a:

in ft yd cm m

Base b:

in ft yd cm m

Side c:

in ft yd cm m

Side d:

in ft yd cm m

HELP

Parallelogram Perimeter Calculator

Base:

in ft yd cm m

Side:

in ft yd cm m

HELP

Triangle Perimeter Calculator

Edge a:

in ft yd cm m

Edge b:

in ft yd cm m

Edge c:

in ft yd cm m

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Circle Circumference Calculator

Radius:

in ft yd cm m

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Ellipse Circumference Calculator

Axis a:

in ft yd cm m

Axis b:

in ft yd cm m

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Sector Perimeter Calculator

Radius:

in ft yd cm m

Angle °:

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Regular Polygon Perimeter Calculator

Side Length:

in ft yd cm m

Number of Sides:

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Perimeter Result:

 

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On this page:

• Calculator
• How to Find the Perimeter of a Shape
• Square Perimeter Formula
• Rectangle Perimeter Formula
• Trapezoid Perimeter Formula
• Parallelogram Perimeter Formula
• Triangle Perimeter Formula
• Circle Perimeter Formula
• Ellipse Perimeter Formula
• Sector Perimeter Formula
• Regular Polygon Perimeter Formula

[ see all ]

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How to Find the Perimeter of a Shape

Perimeter is the length of the outer edge or boundary of a 2-dimensional shape and is expressed in units of length, such as inches or feet. Perimeter is often found by measuring each edge of a shape and adding the edge lengths together to get the total length. The outer edge of a circle or ellipse is referred to as the circumference.

When measuring use the same unit of measurement for each edge, and use our length unit conversion calculators to convert all measurements to the same length if needed.

Square Perimeter Formula

P = 4a

a = edge length

Rectangle Perimeter Formula

P = 2l + 2w

l = length
w = width

Trapezoid Perimeter Formula

P = a + b + c + d

a = base a
b = base b
c = side c
d = side d

Parallelogram Perimeter Formula

P = 2a + 2b

a = side
b = base

Triangle Perimeter Formula

P = a + b + c

a = edge a
b = edge b
c = edge c

Circle Perimeter Formula

P = 2πr

r = radius

Try our circumference calculator to solve using the radius, diameter, or area.

Ellipse Perimeter Formula

P ≈ π[3(a + b) – (((3a + b))(a + 3b))]

a = axis a
b = axis b

Sector Perimeter Formula

P = 2r + ((2θπr) ÷ 360)

r = radius
θ = angle

Regular Polygon Perimeter Formula

P = an

a = edge length
n = number of sides

Use our area calculator to find the area of a shape.