References

Beginner-friendly references for web development, with live, editable examples.

The JavaScript Multiplication * operator

Operator JavaScript All modern browsers Updated
Quick answer

The multiplication operator * multiplies two numbers: 4 * 3 is 12. Like the other arithmetic operators (but unlike +), it coerces string operands to numbers, so "4" * 3 is 12. The compound form *= multiplies and reassigns. For powers, use **.

Overview

* multiplies two numbers — 4 * 3 is 12, 2.5 * 2 is 5. Like subtraction and division, it always does arithmetic, coercing string operands to numbers: "4" * 3 is 12. If an operand can't be converted, the result is NaN.

It follows standard precedence: multiplication (and division) happen before addition and subtraction, so 2 + 3 * 4 is 14, not 20 — use parentheses when you want a different order. There's a compound form, *=, that multiplies and reassigns in one step (x *= 2 doubles x).

Don't confuse * with raising to a power — that's the exponentiation operator ** (2 ** 3 is 8), or Math.pow(). As with all floating-point math, results can carry tiny rounding errors, so round when displaying. And remember overflow doesn't error — a result too large becomes Infinity.

Syntax

a * b

4 * 3        // 12
"4" * 3      // 12  (string coerced)
2 + 3 * 4    // 14  (* before +)
x *= 2;      // multiply and reassign
2 ** 3       // 8   (power - different operator)

Example

Live example 
<pre id="out" style="font:15px ui-monospace,monospace"></pre>
<script>
  const price = 19.99, qty = 3;

  document.getElementById('out').textContent =
    'subtotal: $' + (price * qty).toFixed(2) + '\n' +
    '2 + 3 * 4 = ' + (2 + 3 * 4); // subtotal: $59.97 / 14
</script>

Best practices

  • Remember precedence — * binds before +/-; add parentheses for clarity.
  • Use ** for powers, not repeated multiplication.
  • Use *= to multiply and reassign in one step.
  • Round results when displaying to avoid floating-point artifacts.

Frequently asked questions

How do I multiply numbers in JavaScript?
Use the * operator: 4 * 3 is 12. It coerces string operands to numbers.
What is the difference between * and **?
* multiplies; ** raises to a power. 2 * 3 is 6, but 2 ** 3 is 8.
Why is 2 + 3 * 4 equal to 14?
Because multiplication has higher precedence than addition, so 3 * 4 runs first. Use parentheses, (2 + 3) * 4, to change the order.
What does *= do?
It multiplies and reassigns: x *= 2 is shorthand for x = x * 2.
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