# Boundary vs. Perimeter: What's the Difference?

Edited by Harlon Moss || By Janet White || Updated on September 26, 2023
Boundary represents the dividing line or limit of an area or concept, while Perimeter refers to the continuous line forming the edge of a shape or the sum of the lengths of the sides of a figure.

## Key Differences

Boundary and Perimeter, while related in representing limits or borders, differ in essence and application. A boundary denotes the line that marks the limits of an area, serving as the dividing line between different areas or concepts. It can be physical, such as the boundary of a field, or conceptual, like the boundary between two academic disciplines. It represents the demarcation or separation between different entities, regions, or ideas, establishing clear distinctions and limits.
On the other hand, a perimeter refers to the continuous line forming the boundary of a closed geometrical figure or the sum of the lengths of the sides of a polygon. It is a measurable entity often associated with geometric shapes, defining the outer limits of such shapes. For example, the perimeter of a rectangle is calculated by adding the lengths of all its sides. Unlike a boundary, a perimeter is more specific to geometry and often involves measurement and calculation to determine its length.
The term boundary is more versatile and can be applied to various contexts, be it geographical, mathematical, social, or psychological, to delineate limits or separations. It is not only confined to physical spaces but also to abstract or conceptual domains, illustrating restrictions or distinctions. For instance, ethical boundaries represent the limits of moral conduct and acceptable behavior in a societal context.
Perimeter, in its specialized application, is confined primarily to mathematics and geometry. It quantitatively describes the outer limits of two-dimensional figures, providing a numerical value that represents the total length of the boundaries of a shape. It's a concept that's strictly measurable and is used to understand and analyze geometrical properties and dimensions of different shapes and figures.
In summary, while boundary is a versatile term used to represent the limits or dividing lines between different areas or concepts, both tangible and intangible, perimeter is a more specialized term used predominantly in the context of geometry to represent the continuous line forming the edge of a shape or the sum of the lengths of the sides of a figure.

## Comparison Chart

### Meaning

A line that marks the limits of an area or concept.
The continuous line forming the boundary of a closed geometric figure.

### Application

Various fields including geography and psychology.
Primarily in geometry and mathematics.

### Measurement

May not always be measurable.
Always measurable in terms of length.

### Context

Can be physical or conceptual.
Primarily physical and geometrical.

### Specification

More general and versatile.
More specific and specialized.

## Boundary and Perimeter Definitions

#### Boundary

A line that marks the limits of an area.
The river forms the natural boundary between the two countries.

#### Perimeter

The continuous line forming the boundary of a closed geometric figure.
The perimeter of a square is four times the length of one side.

#### Boundary

A limit of a subject or sphere of activity.
He’s pushing the boundaries of science with his research.

#### Perimeter

The sum of the lengths of the sides of a figure.
The perimeter of the rectangle is the sum of the lengths of all four sides.

#### Boundary

A point or level beyond which something does not extend or occur.
The boundary of human knowledge is ever-expanding.

#### Perimeter

The length of such a boundary.
We calculated the perimeter of the polygon.

#### Boundary

A line that separates two places or regions.
The mountain range is the boundary between the two provinces.

#### Perimeter

The outermost parts or boundary of an area or object.
Guards patrol the perimeter of the compound.

#### Boundary

The scope of a subject or discussion.
The topic is complex and has wide boundaries.

#### Perimeter

A line surrounding a closed figure, area, or object.
The fence marks the perimeter of the field.

#### Boundary

Something that indicates a border or limit.

#### Perimeter

A closed line bounding a plane area.

#### Boundary

The border or limit so indicated.

#### Perimeter

The length of such a line.

#### Boundary

The dividing line or location between two areas.

#### Perimeter

The outer limits of an area.

#### Boundary

The bounds, confines, or limits between immaterial things such as one’s comfort zone, privacy, or professional sphere and the realm beyond.please check this definition along with the example below
I didn’t mean to push the boundaries by sending my boss a message on Saturday night.

#### Perimeter

A defended boundary protecting a military position.

#### Boundary

(cricket) An edge or line marking an edge of the playing field.

#### Boundary

(cricket) An event whereby the ball is struck and either touches or passes over a boundary (with or without bouncing), usually resulting in an award of 4 (four) or 6 (six) runs respectively for the batting team.

#### Perimeter

(mathematics) The sum of the distance of all the lengths of the sides of an object.

#### Boundary

(topology) (of a set) The set of points in the closure of a set $S$, not belonging to the interior of that set.

#### Perimeter

(mathematics) The length of such a boundary.

#### Boundary

That which indicates or fixes a limit or extent, or marks a bound, as of a territory; a bounding or separating line; a real or imaginary limit.
But still his native country liesBeyond the boundaries of the skies.
That bright and tranquil stream, the boundary of Louth and Meath.
Sensation and reflection are the boundaries of our thoughts.

#### Perimeter

The outer limits of an area. circumference

#### Boundary

The line or plane indicating the limit or extent of something

#### Perimeter

A fortified strip or boundary usually protecting a military position.

#### Boundary

A line determining the limits of an area

#### Perimeter

An instrument for determining the extent and shape of the field of vision.

#### Boundary

The greatest possible degree of something;
What he did was beyond the bounds of acceptable behavior
To the limit of his ability

#### Perimeter

The outer boundary of a body or figure, or the sum of all the sides.

#### Perimeter

An instrument for determining the extent and shape of the field of vision.

#### Perimeter

The boundary line or the area immediately inside the boundary

#### Perimeter

A line enclosing a plane areas

#### Perimeter

The size of something as given by the distance around it

## FAQs

#### Is the perimeter always measurable?

Yes, a perimeter is measurable as it is the length of the boundary of a shape.

#### Is a boundary always visible?

No, boundaries can be invisible, representing abstract limits.

#### Can the perimeter refer to the boundary of an area?

Yes, perimeter can mean the outermost parts or boundary of an area or object.

#### Is the perimeter applicable to all shapes?

Yes, any closed shape has a perimeter, which is the length of its outer boundary.

#### Can the perimeter be broken?

Conceptually, a broken perimeter means that the continuous boundary is breached or interrupted.

#### Can a boundary exist in abstract concepts?

Yes, boundaries can exist in abstract domains like knowledge or morality.

#### Can a boundary be immaterial?

Yes, a boundary can be conceptual or immaterial, such as ethical boundaries.

#### Can the boundary represent territorial limits?

Yes, a boundary often represents the dividing line between territories or areas.

#### Is the perimeter of a circle called circumference?

Yes, the perimeter of a circle is specifically called its circumference.

#### Can boundaries be agreed upon by entities?

Yes, political or territorial boundaries are often established by agreements or treaties.

#### Can the perimeter be equal to the boundary?

In geometric terms, the perimeter is the length of the continuous line forming the boundary.

#### Are boundaries essential for defining territories?

Yes, boundaries are essential for defining and distinguishing between different territories.

#### Can the perimeter be a protective barrier?

Yes, perimeter can refer to a protective barrier surrounding an area.

#### Can the boundary be a point of contention?

Yes, boundaries, especially territorial ones, can be points of contention and dispute.

#### Can a boundary be unilateral?

Yes, a boundary can be established unilaterally, though it may lead to disputes.