When writing programs, we often need to perform calculations, compare values, or make decisions.

For example:

• Add two numbers

• Check if a user is 18 or older

• Verify if two values are equal

• Combine conditions like age > 18 AND user is logged in

To perform these operations, JavaScript uses operators.

In this article, we’ll learn the most important operators used in everyday JavaScript programming:

• Arithmetic operators

• Comparison operators

• Logical operators

• Assignment operators

All examples are simple so you can try them directly in your browser console or Node.js.

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What Are Operators?

An operator is a symbol used to perform an operation on values.

Example:

let result = 5 + 3;

Here:

• 5 and 3 are operands

• + is the operator

The operator tells JavaScript what action to perform.

Output:

8

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Arithmetic Operators

Arithmetic operators are used for basic mathematical calculations.

Operator	Meaning	Example
+	Addition	5 + 2
-	Subtraction	5 - 2
*	Multiplication	5 * 2
/	Division	6 / 2
%	Modulus (remainder)	5 % 2

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Addition (+)

let a = 10;
let b = 5;

console.log(a + b);

Output:

15

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Subtraction (-)

console.log(10 - 3);

Output:

7

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Multiplication (*)

console.log(4 * 3);

Output:

12

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Division (/)

console.log(10 / 2);

Output:

5

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Modulus (%)

The modulus operator returns the remainder of a division.

console.log(10 % 3);

Output:

1

Because:

10 ÷ 3 = 3 remainder 1

This operator is commonly used to check even and odd numbers.

Example:

console.log(4 % 2); // 0 (even)
console.log(5 % 2); // 1 (odd)

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Comparison Operators

Comparison operators are used to compare two values.

They always return a boolean value:

• true

• false

Operator	Meaning
==	Equal to
===	Strict equal
!=	Not equal
>	Greater than
<	Less than

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Equal to (==)

== checks if two values are equal, but it converts types if needed.

Example:

console.log(5 == "5");

Output:

true

Because JavaScript converts "5" into the number 5.

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Strict Equal (===)

=== checks both value and type.

Example:

console.log(5 === "5");

Output:

false

Why?

• 5 → number

• "5" → string

Different types, so the result is false.

Most developers prefer using === to avoid unexpected results.

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Not Equal (!=)

Checks if two values are not equal.

Example:

console.log(10 != 5);

Output:

true

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Greater Than (>) and Less Than (<)

console.log(10 > 5);

Output:

true

Example:

console.log(3 < 7);

Output:

true

These are often used in conditions and decision making.

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Logical Operators

Logical operators are used to combine multiple conditions.

Operator	Meaning
&&	AND
!	NOT

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Logical AND (&&)

Returns true only if both conditions are true.

Example:

let age = 20;
let hasID = true;

console.log(age >= 18 && hasID);

Output:

true

Both conditions are true.

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Logical OR (||)

Returns true if at least one condition is true.

Example:

let isWeekend = false;
let isHoliday = true;

console.log(isWeekend || isHoliday);

Output:

true

At least one condition is true.

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Logical NOT (!)

The NOT operator reverses a boolean value.

Example:

let isLoggedIn = false;

console.log(!isLoggedIn);

Output:

true

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Assignment Operators

Assignment operators are used to assign values to variables.

Operator	Example	Meaning
=	x = 5	Assign value
+=	x += 3	Add and assign
-=	x -= 2	Subtract and assign

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Basic Assignment (=)

let score = 10;

This assigns the value 10 to score.

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Addition Assignment (+=)

let score = 10;

score += 5;

console.log(score);

Output:

15

This is the same as writing:

score = score + 5

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Subtraction Assignment (-=)

let score = 10;

score -= 3;

console.log(score);

Output:

7

This is the same as:

score = score - 3

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Operators are a fundamental part of JavaScript because they allow us to:

• Perform calculations

• Compare values

• Combine conditions

• Update variable values

The most commonly used operators include:

• Arithmetic operators → math operations

• Comparison operators → compare values

• Logical operators → combine conditions

• Assignment operators → update variables