FreeKit is a collection of free online tools for developers, SEO professionals, designers, students, content creators, and everyday users.

Are all tools completely free?

Yes. Every tool on FreeKit is free to use without subscriptions or hidden charges.

Do I need to create an account?

No. You can use all tools instantly without creating an account.

No. Most tools process data locally in your browser, and we do not permanently store your inputs.

Can I use FreeKit on mobile devices?

Yes. Every tool is fully responsive and works on smartphones, tablets, laptops, and desktop computers.

How often are new tools added?

We regularly add new tools and improve existing ones based on user feedback and industry needs.

Which browsers are supported?

FreeKit supports all modern browsers, including Chrome, Edge, Firefox, Safari, and other Chromium-based browsers.

Can I share these tools with others?

Absolutely. You are welcome to share FreeKit with friends, colleagues, students, and your team.

What is a number base (radix)?

A number base, also called a radix, is the number of unique digits used to represent numbers in a positional numeral system. Decimal (base 10) uses digits 0–9, binary (base 2) uses 0–1, octal (base 8) uses 0–7, and hexadecimal (base 16) uses 0–9 and A–F. The base determines the place value of each digit — in base N, each position represents a power of N. For example, in binary, the number 101 means 1×2² + 0×2¹ + 1×2⁰ = 5 in decimal.

What is binary and why does it matter?

Binary (base 2) is the fundamental language of computers. Every piece of data in a computer — text, images, video, programs — is ultimately stored as sequences of zeros and ones. Each binary digit (bit) represents a power of 2. Binary is used because electronic circuits have two states: on (1) and off (0). Understanding binary is essential for anyone working with low-level programming, networking, or computer architecture.

What is hexadecimal used for?

Hexadecimal (base 16, or "hex") is widely used in computing because it provides a compact, human-readable way to represent binary data. Each hex digit maps to exactly 4 binary bits, making conversions trivial. Common uses include memory addresses, color codes in web design (e.g., #FF5733), MAC addresses, Unicode code points, and debugging output. Developers frequently use hex to inspect raw byte data or configure hardware registers.

Why do developers need a base converter?

Developers regularly work with multiple number bases in daily tasks. Network engineers deal with subnet masks in binary and hex. Web developers use hex color codes. Systems programmers read memory dumps in hex. Embedded engineers configure hardware registers in binary. Cryptography and security analysts inspect payloads in hex. A base converter saves time and eliminates manual conversion errors when switching between formats during debugging, configuration, or data analysis.

Can this converter handle signed (negative) numbers?

This converter works with non-negative integer values. For signed numbers, computers use techniques like two's complement representation, which differs between bit lengths (8-bit, 16-bit, 32-bit, 64-bit). Two's complement is not a simple base conversion — it depends on the bit width. For example, the 8-bit two's complement of decimal −1 is 11111111 in binary, which as unsigned is 255. Specialized two's complement calculators handle these signed conversions separately.

Does this tool support floating-point or fractional numbers?

This converter focuses on integer values only. Floating-point conversion between bases is significantly more complex because the fractional part may not terminate cleanly in certain bases — for example, decimal 0.1 becomes a repeating fraction in binary (0.0001100110011…). Integer conversion is exact and covers the vast majority of use cases including memory addresses, bitwise operations, color codes, and register values. For floating-point conversion, specialized IEEE 754 converters are recommended.

How do I use this converter for bitwise operations?

First, enter your number and select its current base. The converter shows the binary representation, which is what you need for bitwise operations (AND, OR, XOR, NOT). Copy the binary output, perform your bitwise logic, then enter the result back to convert to your desired base. For example, to find the AND of 0xFF and 0x0F: enter FF in hex, see 11111111 in binary, AND it with 00001111 to get 00001111, then convert back to hex to get 0F.

How does binary relate to data sizes (bytes, kilobytes)?

A byte consists of 8 bits, meaning it can represent 256 distinct values (2⁸ = 256), from 00000000 to 11111111 in binary or 00 to FF in hex. A kilobyte (KB) is roughly 1,000 bytes (technically 1,024 bytes or 2¹⁰), a megabyte (MB) is about 1 million bytes, and so on. Our converter shows the byte representation of your number — for instance, decimal 255 fits in 1 byte as 0xFF, while decimal 65535 requires 2 bytes as 0xFF FF.

How do I convert hex color codes to RGB values?

A hex color code like #FF5733 is actually three hexadecimal byte values packed together: FF (red), 57 (green), and 33 (blue). To convert, enter the two-character hex value for each channel separately in our converter with base 16 selected. FF in hex = 255 in decimal (full red), 57 in hex = 87 in decimal, and 33 in hex = 51 in decimal. So #FF5733 equals rgb(255, 87, 51). Our Base64 Encoder and other developer tools can help with further encoding tasks.

What are custom bases and when would I use base 36?

Custom bases allow you to convert numbers using any radix from 2 to 36. Bases above 10 use letters A–Z as additional digits: A=10, B=11, …, Z=35. Base 36 is the highest standard base and is commonly used for URL shorteners, compact identifiers, and human-friendly codes because it packs the most information per character while remaining readable (using only 0–9 and A–Z). Other notable custom bases include base 32 (used in Base32 encoding) and base 64 (used in Base64 encoding for email attachments).

Number Base Converter

Convert numbers between binary, octal, decimal, and hexadecimal.

IntermediateCalculatorsFreev1.0.0Updated Jul 22, 2025

Number Base Converter

Enter a number and select the input base — all conversions appear instantly

Number Value

Input Base

Quick examples

Enter a number above to see conversions

Supports binary, octal, decimal, hexadecimal, and custom bases 2–36

100% Private — Runs in Your Browser

All base conversions happen locally using JavaScript. Your numbers are never sent to any server, stored, or shared. Close the tab and your data is gone.

How to Use the Number Base Converter

Converting between number bases is fast and simple. Follow these steps:

Enter your number — Type or paste the number you want to convert in the input field.
Select the input base — Choose Binary (2), Octal (8), Decimal (10), Hexadecimal (16), or Custom (2–36) from the dropdown.
View instant results — All four standard base conversions (binary, octal, decimal, hex) appear immediately.
Copy any result — Click the copy button on any output card to copy the value to your clipboard.
Try custom bases — Select "Custom" and enter a base between 2 and 36 for specialized conversions.

Features

Real-time conversion between binary, octal, decimal, and hexadecimal
Support for custom bases from 2 to 36
Bit-length detection (8-bit, 16-bit, 32-bit, 64-bit+)
Byte representation with hex notation (e.g., 0xFF 0x0A)
One-click copy for every output value
Input validation with clear error messages for invalid digits
BigInt precision for large numbers beyond 64 bits
Binary output formatted with 4-bit grouping for readability
Quick example buttons for common conversions
100% browser-based — no server, no data collection

Number Base Systems Explained

Binary (Base 2)

Digits: 0, 1

The language of computers. Every bit is either 0 (off) or 1 (on). Used in all digital systems, networking (IP addresses), and low-level programming.

Octal (Base 8)

Digits: 0–7

Each octal digit represents exactly 3 binary bits. Historically used in Unix file permissions (e.g., chmod 755) and early computing systems.

Decimal (Base 10)

Digits: 0–9

The standard numeral system used by humans worldwide. Most readable for everyday numbers, and the common ground between all base conversions.

Hexadecimal (Base 16)

Digits: 0–9, A–F

Each hex digit maps to 4 binary bits. Used for memory addresses, color codes (#FF5733), MAC addresses, and debugging raw data.

Common Use Cases

Web Development

Convert hex color codes to RGB values. Inspect and decode CSS color values like #3366FF.

Networking

Convert IP addresses between decimal and binary to understand subnet masks and CIDR notation.

Memory Debugging

Convert hex memory addresses to decimal for breakpoint calculations and pointer arithmetic.

Embedded Systems

Convert between hex register values and binary bit fields when configuring hardware peripherals.

Cryptography

Inspect and convert hex-encoded hash values, encryption keys, and certificate serial numbers.

Data Encoding

Understand how Base64 and Base32 encoding work by examining the underlying binary and hex representations.

Education

Learn how number systems work by converting between bases and observing the digit patterns.

Game Development

Convert hex color values and bit-packed game data between formats during shader and texture work.

Conversion Reference Table

Common values shown across all four bases for quick reference:

Decimal	Binary	Octal	Hex
0	0000 0000	000	00
1	0000 0001	001	01
15	0000 1111	017	0F
16	0001 0000	020	10
32	0010 0000	040	20
64	0100 0000	100	40
127	0111 1111	177	7F
128	1000 0000	200	80
255	1111 1111	377	FF
256	0001 0000 0000	400	100
1024	0100 0000 0000	2000	400
65535	1111 1111 1111 1111	177777	FFFF

Tips for Working with Number Bases

To quickly convert between hex and binary, remember that each hex digit = exactly 4 binary bits. Memorize the 16 mappings (0=0000, F=1111) for instant mental conversion.
In binary, the number of bits determines the maximum value: 8 bits = 255, 16 bits = 65,535, 32 bits = 4,294,967,295, 64 bits = 18,446,744,073,709,551,615.
Need to encode data? Try our Base64 Encoder for converting binary data to ASCII-safe text.
Working with unique identifiers? Our UUID Generator creates standard v4 UUIDs in hex format.
Parsing or formatting data? Our JSON Formatter helps inspect API responses that often contain hex-encoded values.
Hex color codes are three byte values: #RRGGBB. Convert each pair of hex digits separately to decimal for RGB (e.g., #FF0000 = rgb(255, 0, 0)).
Unix file permissions use octal: read=4, write=2, execute=1. So chmod 755 means owner=rwx(7), group=r-x(5), others=r-x(5).
When debugging, many tools show memory and register values in hex. Being fluent in hex-to-decimal conversion helps you understand values at a glance.
For strong random identifiers and passwords, check out our Password Generator — it can produce hex-based passwords.
All conversions use your browser's JavaScript BigInt for precision. No data is ever sent to a server.

Frequently Asked Questions

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How to Use the Number Base Converter

Converting between number bases is fast and simple. Follow these steps:

Enter your number — Type or paste the number you want to convert in the input field.

Select the input base — Choose Binary (2), Octal (8), Decimal (10), Hexadecimal (16), or Custom (2–36) from the dropdown.

View instant results — All four standard base conversions (binary, octal, decimal, hex) appear immediately.

Copy any result — Click the copy button on any output card to copy the value to your clipboard.

Try custom bases — Select "Custom" and enter a base between 2 and 36 for specialized conversions.

Features

Real-time conversion between binary, octal, decimal, and hexadecimal

Support for custom bases from 2 to 36

Bit-length detection (8-bit, 16-bit, 32-bit, 64-bit+)

Byte representation with hex notation (e.g., 0xFF 0x0A)

One-click copy for every output value

Input validation with clear error messages for invalid digits

BigInt precision for large numbers beyond 64 bits

Binary output formatted with 4-bit grouping for readability

Quick example buttons for common conversions

100% browser-based — no server, no data collection

Number Base Systems Explained

Binary (Base 2)

Digits: 0, 1

The language of computers. Every bit is either 0 (off) or 1 (on). Used in all digital systems, networking (IP addresses), and low-level programming.

Octal (Base 8)

Digits: 0–7

Each octal digit represents exactly 3 binary bits. Historically used in Unix file permissions (e.g., chmod 755) and early computing systems.

Decimal (Base 10)

Digits: 0–9

The standard numeral system used by humans worldwide. Most readable for everyday numbers, and the common ground between all base conversions.

Hexadecimal (Base 16)

Digits: 0–9, A–F

Each hex digit maps to 4 binary bits. Used for memory addresses, color codes (#FF5733), MAC addresses, and debugging raw data.

Common Use Cases

Web Development

Convert hex color codes to RGB values. Inspect and decode CSS color values like #3366FF.

Networking

Convert IP addresses between decimal and binary to understand subnet masks and CIDR notation.

Memory Debugging

Convert hex memory addresses to decimal for breakpoint calculations and pointer arithmetic.

Embedded Systems

Convert between hex register values and binary bit fields when configuring hardware peripherals.

Cryptography

Inspect and convert hex-encoded hash values, encryption keys, and certificate serial numbers.

Data Encoding

Understand how Base64 and Base32 encoding work by examining the underlying binary and hex representations.

Education

Learn how number systems work by converting between bases and observing the digit patterns.

Game Development

Convert hex color values and bit-packed game data between formats during shader and texture work.

Conversion Reference Table

Common values shown across all four bases for quick reference:

Decimal	Binary	Octal	Hex
0	0000 0000	000	00
1	0000 0001	001	01
15	0000 1111	017	0F
16	0001 0000	020	10
32	0010 0000	040	20
64	0100 0000	100	40
127	0111 1111	177	7F
128	1000 0000	200	80
255	1111 1111	377	FF
256	0001 0000 0000	400	100
1024	0100 0000 0000	2000	400
65535	1111 1111 1111 1111	177777	FFFF

Tips for Working with Number Bases

To quickly convert between hex and binary, remember that each hex digit = exactly 4 binary bits. Memorize the 16 mappings (0=0000, F=1111) for instant mental conversion.

In binary, the number of bits determines the maximum value: 8 bits = 255, 16 bits = 65,535, 32 bits = 4,294,967,295, 64 bits = 18,446,744,073,709,551,615.

Need to encode data? Try our Base64 Encoder for converting binary data to ASCII-safe text.

Working with unique identifiers? Our UUID Generator creates standard v4 UUIDs in hex format.

Parsing or formatting data? Our JSON Formatter helps inspect API responses that often contain hex-encoded values.

Hex color codes are three byte values: #RRGGBB. Convert each pair of hex digits separately to decimal for RGB (e.g., #FF0000 = rgb(255, 0, 0)).

Unix file permissions use octal: read=4, write=2, execute=1. So chmod 755 means owner=rwx(7), group=r-x(5), others=r-x(5).

When debugging, many tools show memory and register values in hex. Being fluent in hex-to-decimal conversion helps you understand values at a glance.

For strong random identifiers and passwords, check out our Password Generator — it can produce hex-based passwords.

All conversions use your browser's JavaScript BigInt for precision. No data is ever sent to a server.

Frequently Asked Questions