# Variable vs. Constant: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on November 24, 2023
A Variable is subject to change, while a Constant remains unchanging over time.

## Key Differences

A Variable, by definition, denotes something that can vary or change depending on different factors or conditions. In contrast, a Constant is something that remains steady and unchanged, irrespective of external influences.
In the realm of mathematics and science, a Variable represents quantities that can assume different values. On the other hand, a Constant symbolizes a value that is fixed and does not alter, providing stability in equations and formulas.
When thinking about characteristics or properties, a Variable attribute might change under different circumstances or over time. A Constant attribute, however, remains consistent and can be relied upon to stay the same.
Variables play a crucial role in experiments and research, where they might be manipulated or observed for changes. Constants, conversely, ensure that other factors stay consistent, allowing for accurate assessments of Variables.
In everyday language, referring to something as a Variable suggests uncertainty or fluctuation, while labeling something as a Constant implies reliability and steadfastness.

## Comparison Chart

### Definition

Subject to change
Remains unchanged

### Role in Mathematics

Represents changeable quantities
Represents unchangeable values

### Characteristics

Alters under different circumstances
Consistently remains the same

### In Experiments

Can be manipulated or observed
Kept stable for accuracy

### Implication in Language

Suggests uncertainty or fluctuation

## Variable and Constant Definitions

#### Variable

A symbol in math that represents an unknown quantity.
In the equation x + 2 = 5, 'x' is the Variable.

#### Constant

A quantity that remains unchanged in mathematical equations.
The speed of light is a Constant in physics.

#### Variable

An element, feature, or factor that can vary.
There are several Variables affecting the stock market today.

#### Constant

Faithful and dependable.
He's been a Constant friend through tough times.

#### Variable

Subject to variation or changes.
His moods are extremely Variable.

#### Constant

Not changing or varying; continuous
A constant gentle rain.
Drove at a constant speed.

#### Variable

Likely to change or vary; subject to variation; changeable.

#### Constant

Happening regularly or repeatedly; continual
The constant barking of the dog next door.
Constant interruptions.

#### Variable

Inconstant; fickle.

#### Constant

Unchanging in nature, value, or extent; invariable
A constant wind speed.

#### Variable

(Biology) Tending to exhibit genetic variation or variation in a physical trait
Geographically variable color patterns.

#### Constant

Steadfast in purpose, loyalty, or affection; faithful
A constant friend.

#### Variable

(Mathematics) Having no fixed quantitative value.

#### Constant

Something that is unchanging or invariable.

#### Variable

Something that varies or is prone to variation.

#### Constant

A quantity assumed to have a fixed value in a specified mathematical context.

#### Variable

(Astronomy) A variable star.

#### Constant

An experimental or theoretical condition, factor, or quantity that does not vary or that is regarded as invariant in specified circumstances.

#### Variable

A quantity capable of assuming any of a set of values.

#### Constant

Unchanged through time or space; permanent.

#### Variable

A symbol representing such a quantity. For example, in the expression a2 + b2 = c2, a,b, and c are variables.

#### Constant

Consistently recurring over time; persistent.

#### Variable

Able to vary or be varied.
Variable winds or seasons; a variable quantity; a variable resistor

#### Constant

Steady in purpose, action, feeling, etc.

Likely to vary.

#### Constant

Firm; solid; not fluid.

#### Variable

Marked by diversity or difference.

#### Constant

(obsolete) Consistent; logical.

#### Variable

(mathematics) Having no fixed quantitative value.

#### Constant

Bounded above by a constant.
Constant time
Constant space

#### Variable

(biology) Tending to deviate from a normal or recognized type.

#### Constant

That which is permanent or invariable.

#### Variable

Something that is variable.

#### Constant

(algebra) A quantity that remains at a fixed value throughout a given discussion.

#### Variable

Something whose value may be dictated or discovered.
There are several variables to consider here.

#### Constant

(science) Any property of an experiment, determined numerically, that does not change under given circumstances.

#### Variable

(mathematics) A symbol representing a variable.

#### Constant

(computing) An identifier that is bound to an invariant value; a fixed value given a name to aid in readability of source code.

#### Variable

(programming) A named memory location in which a program can store intermediate results and from which it can read them.

#### Constant

Firm; solid; fixed; immovable; - opposed to fluid.
If . . . you mix them, you may turn these two fluid liquors into a constant body.

#### Variable

(astronomy) A variable star.

#### Constant

Not liable, or given, to change; permanent; regular; continuous; continually recurring; steadfast; faithful; not fickle. Opposite of changeable and variable.
Both loving one fair maid, they yet remained constant friends.
I am constant to my purposes.
His gifts, his constant courtship, nothing gained.
Onward the constant current sweeps.

#### Variable

(nautical) A shifting wind, or one that varies in force.

#### Constant

Remaining unchanged or invariable, as a quantity, force, law, etc.

#### Variable

Those parts of the sea where a steady wind is not expected, especially the parts between the trade-wind belts.

#### Constant

Consistent; logical.

#### Variable

Having the capacity of varying or changing; capable of alternation in any manner; changeable; as, variable winds or seasons; a variable quantity.

#### Constant

That which is not subject to change; that which is invariable.

#### Variable

Liable to vary; too susceptible of change; mutable; fickle; unsteady; inconstant; as, the affections of men are variable; passions are variable.
Lest that thy love prove likewise variable.
His heart, I know, how variable and vain!

#### Constant

A quantity that does not change its value; - used in countradistinction to variable.

#### Variable

That which is variable; that which varies, or is subject to change.

#### Constant

A number whose value, when ascertained (as by observation) and substituted in a general mathematical formula expressing an astronomical law, completely determines that law and enables predictions to be made of its effect in particular cases.

#### Variable

A quantity which may increase or decrease; a quantity which admits of an infinite number of values in the same expression; a variable quantity; as, in the equation x2 - y2 = R2, x and y are variables.

#### Constant

A number expressing some property or condition of a substance or of an instrument of precision; as, the dielectric constant of quartz; the collimation constant of a transit instrument.

#### Variable

A shifting wind, or one that varies in force.

#### Constant

A data structure that does not change during the course of execution of a program. It may be a number, a string, or a more complex data structure; - contrasted with variable.

#### Variable

Something that is likely to vary; something that is subject to variation;
The weather is one variable to be considered

#### Constant

A quantity that does not vary

#### Variable

A quantity that can assume any of a set of values

#### Constant

A number representing a quantity assumed to have a fixed value in a specified mathematical context;
The velocity of light is a constant

#### Variable

A star that varies noticeably in brightness

#### Constant

Persistent in occurrence and unvarying in nature;
Maintained a constant temperature
A constant beat
Principles of unvarying validity

#### Variable

A symbol (like x or y) that is used in mathematical or logical expressions to represent a variable quantity

#### Constant

Continually recurring or continuing without interruption;
Constant repetition of the exercise
Constant chatter of monkeys

#### Variable

Liable to or capable of change;
Rainfall in the tropics is notoriously variable
Variable winds
Variable expenses

#### Constant

Steadfast in purpose or devotion or affection;
A man constant in adherence to his ideals
A constant lover
Constant as the northern star

#### Variable

Marked by diversity or difference;
The varying angles of roof slope
Nature is infinitely variable

#### Constant

Uninterrupted in time and indefinitely long continuing;
The ceaseless thunder of surf
In constant pain
Night and day we live with the incessant noise of the city
The never-ending search for happiness
The perpetual struggle to maintain standards in a democracy
Man's unceasing warfare with drought and isolation
Unremitting demands of hunger

#### Variable

(used of a device) designed so that a property (as e.g. light) can be varied;
A variable capacitor
Variable filters in front of the mercury xenon lights

#### Constant

Remaining unchanged over time.
Her Constant dedication to the job is commendable.

#### Variable

Something that can change or be changed.
The weather is a classic Variable in outdoor events.

#### Constant

Continuously occurring or persistently recurring.
The drone of machinery was a Constant presence in the factory.

#### Variable

Something that is not consistent or having a fixed pattern.
Variable winds made the sailing race challenging.

#### Constant

A situation or state of affairs that does not change.
Change seems to be the only Constant in life.

## FAQs

#### Is the value of a Constant always the same in every scenario?

While a Constant remains unchanged within a specific context, different scenarios might have different constants.

#### How do Variables impact research studies?

Variables are factors in studies that can influence outcomes, and researchers often manipulate or observe them.

#### What defines a Constant in mathematics?

In mathematics, a Constant is a value that remains fixed and unaltered.

#### Can a Variable become a Constant in an experiment?

Yes, a Variable can be controlled and kept unchanging, making it a Constant in that context.

#### What is the primary characteristic of a Variable?

A Variable is primarily characterized by its ability to change.

#### Can the term Variable refer to non-mathematical situations?

Yes, Variable can refer to anything subject to change, like Variable weather conditions.

#### Is a Constant always a numerical value?

No, a Constant can be any unchanging factor, not just numerical.

#### How does a Variable differ in algebra versus statistics?

In algebra, a Variable represents an unknown quantity, while in statistics, it might represent data points or attributes subject to variation.

#### Are all Variables unpredictable?

Not necessarily; while Variables can change, they might follow predictable patterns or trends.

#### What's an example of a Constant in daily life?

The number of hours in a day, 24, is a Constant in daily life.

#### Why are Constants essential in scientific experiments?

Constants ensure other factors remain steady, allowing researchers to accurately study the effects of Variables.

#### Can Constants help provide stability?

Yes, Constants offer a stable, unchanging factor in varying contexts.

#### Do all equations have both Variables and Constants?

No, some equations might only have Variables, only Constants, or a mix of both.

#### Are Constants always known quantities?

Typically, Constants are known quantities in a given context, but they might need to be determined in some scenarios.

#### Do Constants have a role beyond math and science?

Yes, Constants can symbolize unchanging truths or principles in various fields, including philosophy and ethics.

#### Can a Variable represent more than one value?

Yes, a Variable can take on multiple values, especially in different instances or scenarios.

#### How can understanding Variables and Constants aid problem-solving?

Recognizing what can change (Variables) and what remains steady (Constants) provides clarity when analyzing and resolving issues.

#### Why might we use a Variable in a mathematical expression?

Variables allow for generality in expressions and can represent unknowns that we aim to determine.

#### Can Constants ever change in different contexts?

Yes, what's Constant in one context may vary in another.

#### Why might a Variable be essential in decision-making?

Variables represent factors that might change, so considering them helps make informed decisions.