JavaScript Number Methods

Beginner

⏱️ 6 min read

📚 Updated: Jul 2026

🎯 10 Tutorials

Number.prototype

JavaScript Number methods hub — toString and formatting tutorials

Overview

What You’ll Learn

JavaScript Number methods help you convert and format numeric values for the UI, APIs, and debugging. This hub indexes 10 tutorials with examples and try-it labs.

toString

Any base

Radix

2–36

Hex / bin

Colors & bits

Display

UI text

Safe

Baseline

10 guides

Growing

Fundamentals

Introduction

A JavaScript Number is an IEEE-754 floating-point value. Instance methods live on Number.prototype. Static methods like Number.isFinite(), Number.isInteger(), Number.isNaN(), Number.isSafeInteger(), Number.parseInt(), and Number.parseFloat() are called on Number itself.

Start with toString() to learn decimal strings and optional radix conversion for binary and hex.

Quick peek

👀 Number → String in One Call

The same method adapts to the base you need:

(255).toString() → "255" (255).toString(16) → "ff" (6).toString(2) → "110" (-10).toString(2) → "-1010"

Number Methods Index

Search by method name or browse by category. Each tutorial includes syntax, five try-it examples, and FAQs.

Search Number methods

Convert to String

4 tutorials

Turn numbers into text for display, fixed decimals, significant digits, scientific notation, colors, and base conversion.

Method	Description	Tutorial
`toString()`	Return a string for a number in base 2–36 — default decimal, binary/hex via radix, keeps the minus sign for negatives.	Open
`toExponential()`	Format a number in exponential (scientific) notation — optional fractionDigits 0–100 for mantissa precision.	Open
`toFixed()`	Format a number with a fixed count of decimal places — rounds, pads zeros, returns a display string.	Open
`toPrecision()`	Format a number to a chosen count of significant digits — may use plain or exponential form.	Open

Static Methods

6 tutorials

Call on Number itself (not on number instances) to inspect, validate, or parse values.

Method	Description	Tutorial
`isFinite()`	Static check: return true only for finite number values — no coercion, rejects Infinity, NaN, and non-numbers.	Open
`isInteger()`	Static check: return true only for integer number values — no coercion, rejects floats, Infinity, NaN, and non-numbers.	Open
`isNaN()`	Static check: return true only for the number value NaN — no coercion, safer than global isNaN().	Open
`isSafeInteger()`	Static check: return true only for integers in the MAX_SAFE_INTEGER / MIN_SAFE_INTEGER range — no coercion.	Open
`parseInt()`	Static parse: turn a string into an integer with optional radix 2–36 — same as global parseInt.	Open
`parseFloat()`	Static parse: turn a string into a floating-point number — keeps decimals, same as global parseFloat.	Open

❓ Frequently Asked Questions

What are JavaScript Number methods?

Number methods include instance formatters on Number.prototype (toString, toFixed, and so on) and static helpers on Number itself — for example Number.isFinite(), Number.isInteger(), Number.isNaN(), Number.isSafeInteger(), Number.parseInt(), and Number.parseFloat().

What should I learn first?

Start with toString() for text and base conversion, then formatting methods. For validation and parsing, learn Number.isFinite(), Number.isInteger(), Number.isNaN(), Number.isSafeInteger(), Number.parseInt(), and Number.parseFloat().

Do Number methods change the original value?

Conversion and formatting methods return a new string or number. They do not mutate the original primitive — numbers are immutable values.

What is a static Number method?

A static method is called on Number itself, such as Number.parseFloat(s) or Number.isSafeInteger(x). It is not called on a number instance like (5).parseFloat().

How is Number different from BigInt?

Number uses floating-point and loses precision above Number.MAX_SAFE_INTEGER. BigInt handles arbitrary-size integers. Use BigInt for huge exact integer base conversions.

Where are the Number method tutorials?

Open toString(), toExponential(), toFixed(), toPrecision(), isFinite(), isInteger(), isNaN(), isSafeInteger(), parseInt(), or parseFloat() from the index below for syntax, examples, five try-it labs each, and FAQs.