JavaScript Number POSITIVE_INFINITY Property

What You’ll Learn

Number.POSITIVE_INFINITY is a static data property on Number (same API as MDN Number.POSITIVE_INFINITY). It is the positive Infinity value — the same as global Infinity. You get it when math overflows past MAX_VALUE, or from expressions like 1 / 0. This tutorial covers detection, IEEE-754 rules, five examples, and try-it labs.

Introduction

IEEE-754 floating point includes special non-finite values. Number.POSITIVE_INFINITY is how JavaScript names positive infinity — larger than every finite Number, including Number.MAX_VALUE.

It is the same value as the global Infinity identifier ((Number.POSITIVE_INFINITY === Infinity). Prefer the Number. form when you want infinity grouped with other Number constants, and because Number.POSITIVE_INFINITY is non-writable.

This page is part of JavaScript Number Properties. Related tools include Number.isFinite(), Number.MAX_VALUE, and the twin constant Number.NEGATIVE_INFINITY.

Understanding the POSITIVE_INFINITY Property

Positive infinity is not a huge finite number — it is a special IEEE-754 value. Once a result becomes Infinity, further math often stays infinite (or becomes NaN in indeterminate cases like Infinity / Infinity).

• It is a constant number, not a method.
• Same value as global Infinity.
• Greater than every finite Number: Number.POSITIVE_INFINITY > Number.MAX_VALUE.
• Detect overflow with === Number.POSITIVE_INFINITY or !Number.isFinite(x).

📝 Syntax

General form of the static property Number.POSITIVE_INFINITY:

Number.POSITIVE_INFINITY

Value

The same as the global Infinity property.

Property attributes

Common patterns

Number.POSITIVE_INFINITY;                 // Infinity
Number.POSITIVE_INFINITY === Infinity;    // true
Number.MAX_VALUE * 2;                     // Infinity
1 / 0;                                    // Infinity

Number.isFinite(Number.POSITIVE_INFINITY); // false

function checkNumber(bigNumber) {
  if (bigNumber === Number.POSITIVE_INFINITY) {
    return "Process number as Infinity";
  }
  return bigNumber;
}

Examples Gallery

Examples follow MDN Number.POSITIVE_INFINITY patterns. Use View Output or Try It Yourself for each case.

Number.POSITIVE_INFINITY;
Number.POSITIVE_INFINITY === Infinity;  // true

Infinity
true

Number.MAX_VALUE * 2;  // Infinity

Infinity

function checkNumber(bigNumber) {
  if (bigNumber === Number.POSITIVE_INFINITY) {
    return "Process number as Infinity";
  }
  return bigNumber;
}

checkNumber(Number.MAX_VALUE);      // 1.7976931348623157e+308
checkNumber(Number.MAX_VALUE * 2);  // "Process number as Infinity"

1.7976931348623157e+308
Process number as Infinity

1 / 0;                                  // Infinity
1 / 0 === Number.POSITIVE_INFINITY;     // true
1 / Number.POSITIVE_INFINITY;           // 0

Infinity
true
0

typeof Number.POSITIVE_INFINITY;                 // "number"
Number.isFinite(Number.POSITIVE_INFINITY);       // false
Number.POSITIVE_INFINITY > Number.MAX_VALUE;     // true

number
false
true

🚀 Common Use Cases

• Overflow detection — compare results to Number.POSITIVE_INFINITY.
• Sentinel / clamp — some algorithms use ±Infinity as open bounds.
• Graphics / physics — represent unbounded distances carefully.
• Validation — reject non-finite inputs with Number.isFinite.
• Not for errors by default — MDN notes NaN is often a better failure signal.
• Teaching IEEE-754 — show that 1 / 0 is defined as Infinity in JS.

📝 Notes

• This is a static property — use Number.POSITIVE_INFINITY only.
• Do not write Number.POSITIVE_INFINITY() — it is not a function.
• Number.POSITIVE_INFINITY === Infinity is true.
• 0 * Infinity and Infinity / Infinity are NaN.
• Negative twin: Number.NEGATIVE_INFINITY.
• Prefer Number.isFinite() to reject all non-finite values.

💡 Best Practices