Protractor vs. Compass — What's the Difference?

By Tayyaba Rehman & Fiza Rafique — Updated on May 3, 2024
Protractors measure angles in degrees, typically made of transparent plastic or glass; compasses are drafting tools used for drawing circles or arcs.

Key Differences

A protractor is primarily used for measuring angles, commonly found in educational settings where geometry is taught. On the other hand, a compass is used for drawing circles or arcs, crucial in both educational and professional drafting environments.
Protractors typically feature a semicircular design marked with degrees from 0 to 180. Whereas, compasses consist of two legs connected at a pivot; one leg has a point to anchor the tool, and the other holds a pencil to draw.
The material of a protractor is usually transparent plastic or glass to easily see the base lines and angles being measured. Conversely, compasses are often made of metal for stability and precision, with some high-end models also incorporating adjustment mechanisms for more accurate control.
While protractors provide static measurements of angles, compasses offer dynamic use, allowing the user to adjust the radius and create multiple sizes of circles or arcs based on the distance between the legs.
Protractors are often used in conjunction with rulers and straightedges to measure and draw precise angles. In contrast, compasses can be used independently to construct the needed geometric figures without additional tools.

Comparison Chart

Primary Use

Measuring angles
Drawing circles or arcs

Design

Semicircular, marked in degrees
Two legs with a pivot, one leg with a pencil

Material

Transparent plastic or glass
Typically metal

Method of Use

Static measurement

Dependency on Tools

Used with rulers and straightedges
Can be used independently

Compare with Definitions

Protractor

Collaborates with other tools for accurate measurements.
She aligned her protractor with the straightedge to measure the angle precisely.

Compass

Often used in drafting and design.
The architect used a compass to sketch the initial design of the roundel.

Protractor

Usually semicircular in shape and marked in degrees.
Her protractor was made of clear plastic, making it easy to read the degrees.

Compass

A tool used for drawing circles or arcs.
He adjusted the compass to draw a perfect circle on the blueprint.

Protractor

Used in educational and engineering contexts.
In geometry class, everyone had a ruler and a protractor for the exercise.

Compass

Consists of two legs hinged together.
The compass legs adjusted smoothly, allowing for precise control of the radius.

Protractor

The transparency of the protractor helped him align it properly on the drawing.

Compass

One leg has a point, the other holds a drawing implement.
The pointed leg of the compass was anchored firmly on the paper.

Protractor

A tool used for measuring angles.
The student used a protractor to measure the angle of the triangle.

Compass

Provides dynamic measurements and constructions.
Adjusting the compass, she created several arcs for the design.

Protractor

A protractor is a measuring instrument, typically made of transparent plastic or glass, for measuring angles. Some protractors are simple half-discs or full circles.

Compass

A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with magnetic north.

Protractor

A semicircular instrument for measuring and constructing angles.

Compass

An instrument containing a magnetized pointer which shows the direction of magnetic north and bearings from it
Walkers should be equipped with a map and compass
A magnetic compass
Crewe was ideally placed on the rail network, with connections running to all points of the compass

Protractor

(Anatomy) A muscle that extends a limb or other part.

Compass

An instrument for drawing circles and arcs and measuring distances between points, consisting of two arms linked by a movable joint, one arm ending in a point and the other usually carrying a pencil or pen
A regular heptagon cannot be constructed accurately with only ruler and compass

Protractor

One who, or that which, protracts, or causes protraction.

Compass

The range or scope of something
The event had political repercussions which are beyond the compass of this book
Goods and services which fall within the compass of the free market

Protractor

A circular or semicircular tool for drawing or measuring angles.

Compass

Go round (something) in a circular course
The ship wherein Magellan compassed the world

Protractor

(surgery) An instrument formerly used in extracting foreign or offensive matter from a wound.

Compass

Contrive to accomplish (something)
He compassed his end only by the exercise of violence

Protractor

(anatomy) A muscle that extends an organ or part; opposed to retractor.

Compass

A device used to determine geographic direction, usually consisting of a magnetic needle or needles horizontally mounted or suspended and free to pivot until aligned with the earth's magnetic field.

Protractor

An adjustable pattern used by tailors.

Compass

Another device, such as a radio compass or a gyrocompass, used for determining geographic direction.

Protractor

One who, or that which, protracts, or causes protraction.

Compass

A V-shaped device for describing circles or circular arcs and for taking measurements, consisting of a pair of rigid, end-hinged legs, one of which is equipped with a pen, pencil, or other marker and the other with a sharp point providing a pivot about which the drawing leg is turned. Also called pair of compasses.

Protractor

A mathematical instrument for laying down and measuring angles on paper, used in drawing or in plotting. It is of various forms, semicircular, rectangular, or circular.

Compass

Awareness or understanding of one's purpose or objectives
"Lacking a coherent intellectual and moral commitment, [he] was forced to find his compass in personal experience" (Doris Kearns Goodwin).

Protractor

An instrument formerly used in extracting foreign or offensive matter from a wound.

Compass

An enclosing line or boundary; a circumference
Outside the compass of the fence.

Protractor

A muscle which extends an organ or part; - opposed to retractor.

Compass

A restricted space or area
Four huge crates within the compass of the elevator.

Protractor

An adjustable pattern used by tailors.

Compass

Range or scope, as of understanding, perception, or authority
The subject falls outside the compass of this study.

Protractor

Drafting instrument used to draw or measure angles

Compass

(Music) See range.

Compass

To make a circuit of; circle
The sailboat compassed the island.

Compass

To surround; encircle
The trees compass the grave.

Compass

To understand; comprehend
"God ... is too great a profundity to be compassed by human cerebration" (Flann O'Brian).

Compass

"He compassed his end only by the exercise of gentle violence" (Henry James).

Compass

To gain or achieve
"She had compassed the high felicity of seeing the two men beautifully take to each another" (Henry James).

Compass

To scheme; plot
Compass the death of the king.

Forming a curve.

Compass

A magnetic or electronic device used to determine the cardinal directions (usually magnetic or true north).

Compass

A pair of compasses (a device used to draw an arc or circle).

Compass

(music) The range of notes of a musical instrument or voice.

Compass

(obsolete) A space within limits; an area.

Compass

(obsolete) An enclosing limit; a boundary, a circumference.
Within the compass of an encircling wall

Compass

Moderate bounds, limits of truth; moderation; due limits; used with within.

(archaic) Scope.

Compass

(obsolete) Range, reach.

Compass

(obsolete) A passing round; circuit; circuitous course.

Compass

To surround; to encircle; to environ; to stretch round.

Compass

To go about or round entirely; to traverse.

Compass

(dated) To accomplish; to reach; to achieve; to obtain.

Compass

(dated) To plot; to scheme (against someone).

Compass

(obsolete) In a circuit; round about.

Compass

A passing round; circuit; circuitous course.
They fetched a compass of seven day's journey.
This day I breathed first; time is come round,And where I did begin, there shall I end;My life is run his compass.

Compass

An inclosing limit; boundary; circumference; as, within the compass of an encircling wall.

Compass

An inclosed space; an area; extent.
Their wisdom . . . lies in a very narrow compass.

Compass

Extent; reach; sweep; capacity; sphere; as, the compass of his eye; the compass of imagination.
The compass of his argument.

Compass

Moderate bounds, limits of truth; moderation; due limits; - used with within.
In two hundred years before (I speak within compass), no such commission had been executed.

Compass

The range of notes, or tones, within the capacity of a voice or instrument.
You would sound me from my lowest note to the top of my compass.

Compass

An instrument for determining directions upon the earth's surface by means of a magnetized bar or needle turning freely upon a pivot and pointing in a northerly and southerly direction.
He that first discovered the use of the compass did more for the supplying and increase of useful commodities than those who built workhouses.

Compass

A pair of compasses.
To fix one foot of their compass wherever they please.

Compass

A circle; a continent.
The tryne compas [the threefold world containing earth, sea, and heaven. Skeat.]
Its leaves are turned to the north as true as the magnet:This is the compass flower.

Compass

To go about or entirely round; to make the circuit of.
Ye shall compass the city seven times.
We the globe can compass soon.

Compass

To inclose on all sides; to surround; to encircle; to environ; to invest; to besiege; - used with about, round, around, and round about.
With terrors and with clamors compassed round.
Thine enemies shall cast a trench about thee, and compass thee round.

Compass

To reach round; to circumvent; to get within one's power; to obtain; to accomplish.
If I can check my erring love, I will:If not, to compass her I'll use my skill.
How can you hope to compass your designs?

Compass

To curve; to bend into a circular form.

Compass

To purpose; to intend; to imagine; to plot.
Compassing and imagining the death of the king are synonymous terms; compassing signifying the purpose or design of the mind or will, and not, as in common speech, the carrying such design to effect.

Compass

An area in which something acts or operates or has power or control:
The range of a supersonic jet
The ambit of municipal legislation
Within the scope of an investigation
Outside the reach of the law
In the political orbit of a world power

Compass

The limit of capability;
Within the compass of education

Compass

Drafting instrument used for drawing circles

Compass

This writer attempts more than his talents can compass

Compass

Travel around, either by plane or ship;
We compassed the earth

Compass

Get the meaning of something;
Do you comprehend the meaning of this letter?

Common Curiosities

What materials are compasses typically made of?

Compasses are typically made of metal for durability and precision.

How do you use a protractor to measure an angle?

Align the baseline of the protractor with one leg of the angle and read the degree measurement where the other leg intersects the protractor.

What is the main use of a compass?

A compass is primarily used to draw circles or arcs.

Are there different types of protractors?

Yes, there are full-circle protractors and semicircular protractors.

Can a protractor measure full circles?

No, a typical protractor measures up to 180 degrees, half a circle.

How does a compass work?

A compass works by adjusting the distance between its legs to change the radius of the circle or arc being drawn.

What is the main use of a protractor?

A protractor is primarily used to measure angles in degrees.

Are there different types of compasses?

Yes, there are simple compasses for basic use and precision compasses with fine adjustments.

Is a protractor used in professional settings?

Yes, protractors are used in various professional fields, including engineering and architecture.

Can a compass be used without other tools?

Yes, a compass can be used independently to draw circles and arcs.

Can a protractor measure angles greater than 180 degrees?

Some specialized protractors can measure angles greater than 180 degrees, but typical ones cannot.

What are the educational applications of a protractor and a compass?

Both tools are extensively used in geometry classes to teach about angles, circles, and other geometric concepts.

What ensures the precision of a compass?

The quality of the hinge and the stability of the pivot point ensure precision.

What is the importance of the transparency of a protractor?

The transparency allows for better visibility and accurate alignment over the base lines.

How do I adjust a compass for different circle sizes?

Adjust the distance between the legs of the compass to change the radius of the circle.

Share via Social Media
Embed This Content
Embed Code
Share Directly via Messenger