# JavaScript language overview — Numbers

> JavaScript has two built-in numeric types: Number and BigInt.

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## Knowledge

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JavaScript has two built-in numeric types: Number and BigInt.

The Number type is an IEEE 754 64-bit double-precision floating point value, which means integers can be safely represented between -(253 − 1) and 253 − 1 without loss of precision, and floating point numbers can be stored all the way up to 1.79 × 10308. Within numbers, JavaScript does not distinguish between floating point numbers and integers.

So an _apparent integer_ is in fact _implicitly a float_. Because of IEEE 754 encoding, sometimes floating point arithmetic can be imprecise.

For operations that expect integers, such as bitwise operations, the number will be converted to a 32-bit integer.

Number literals can also have prefixes to indicate the base (binary, octal, decimal, or hexadecimal), or an exponent suffix.

The BigInt type is an arbitrary length integer. Its behavior is similar to C's integer types (e.g., division truncates to zero), except it can grow indefinitely. BigInts are specified with a number literal and an n suffix.

The standard arithmetic operators are supported, including addition, subtraction, remainder arithmetic, etc. BigInts and numbers cannot be mixed in arithmetic operations.

The {{jsxref("Math")}} object provides standard mathematical functions and constants.

There are three ways to convert a string to a number

{{jsxref("parseInt()")}}, which parses the string for an integer. {{jsxref("parseFloat()")}}, which parses the string for a floating-point number. The Number() function, which parses a string as if it's a number literal and supports many different number representations.

You can also use the unary plus + as a shorthand for Number().

Number values also include {{jsxref("NaN")}} (short for "Not a Number") and {{jsxref("Infinity")}}. Many "invalid math" operations will return NaN — for example, if attempting to parse a non-numeric string, or using Math.log() on a negative value. Division by zero produces Infinity (positive or negative).

NaN is contagious: if you provide it as an operand to any mathematical operation, the result will also be NaN. NaN is the only value in JavaScript that's not equal to itself (per IEEE 754 specification).

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