What is binary (base 2)?

Binary is the native number system of computers. Every integer is represented using only the digits 0 and 1. Each digit position represents a power of 2: the rightmost is 2^0 (1), then 2^1 (2), 2^2 (4), 2^3 (8), and so on. The decimal number 10 is 1010 in binary (8 + 2).

What is hexadecimal (base 16) and why do developers use it?

Hexadecimal uses 16 digits: 0–9 and A–F. Developers prefer hex because it maps cleanly to binary: each hex digit represents exactly 4 binary digits (a nibble). This makes hex a compact way to express binary values — the 8-bit byte 11111111 is simply FF in hex, and 32-bit memory addresses fit in 8 hex characters. CSS color values (#FF6600), file magic bytes, and network masks are all commonly expressed in hex.

What is the difference between encodeURI and encodeURIComponent?

encodeURI is designed for complete URLs — it leaves the structural characters (: / ? # & = + @) untouched so the URL remains valid. encodeURIComponent is designed for individual values within a URL — it encodes those structural characters too, preventing them from being misinterpreted as URL delimiters. Use encodeURIComponent for query parameter values; use encodeURI only if you have a full URL that you want to sanitise without breaking its structure.

Why does a space sometimes appear as + instead of %20?

HTML forms using application/x-www-form-urlencoded encoding replace spaces with + rather than %20. Both are valid in query strings, but they are different encodings. Modern APIs and URLs use %20 (RFC 3986). If you are constructing a query string for a form submission, check whether the receiving server expects + or %20.

Tool comparison

Number Base Converter vs URL Encoder / Decoder

Number Base Converter and URL Encoder / Decoder are both encoding tools. They serve related purposes but are optimised for different tasks — understanding the distinction helps you choose the right one for your workflow.

Bottom line

Number Base Converter changes how a number is represented (binary, octal, decimal, hex). URL Encoder escapes special characters so they are safe in a URL. Both produce different string representations of data, but they operate on different types: numeric values vs text strings.

What each tool does

Number Base Converter

The Number Base Converter converts integers between the four bases used in computing: binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Enter a number in any base and the tool returns all four representations instantly — no manual arithmetic required. It also returns a grouped binary format (4-digit nibbles) and grouped hex (2-digit bytes) for easier reading, the bit length of the value, and whether it is a power of two.

Open Number Base Converter →

URL Encoder / Decoder

Percent-encoding (also called URL encoding) is a mechanism defined in RFC 3986 for representing characters that are not allowed or have special meaning in a URL. Every character that needs encoding is replaced by a percent sign followed by two hex digits representing the character's UTF-8 byte value — for example, a space becomes %20 and an ampersand becomes %26. There are two encoding variants: component encoding (encodeURIComponent) converts every character except the unreserved set A–Z a–z 0–9 and - _ . ! ~ * ' ( ); full URL encoding (encodeURI) additionally preserves the structural characters : / ? # [ ] @ ! $ & ' ( ) * + , ; = so that a complete URL remains navigable. Decoding reverses the process, converting all %XX sequences back to the original characters. URL encoding is required whenever you embed user-supplied text in a query string, form a redirect URL, construct a OAuth callback, or pass data through a system that only allows safe ASCII characters.

Open URL Encoder / Decoder →

Side-by-side comparison

Feature	Number Base Converter	URL Encoder / Decoder
Category	encoding	encoding
Primary purpose	Convert numbers between binary, octal, decimal, and hexadecimal.	Encode or decode URLs and query string components using percent-encoding (RFC 3986).
Inputs	input, from_base	input, mode
Outputs	input_normalized, from_base, decimal, binary, octal, hexadecimal, binary_grouped, hex_grouped, bit_length, is_power_of_two	output, mode, changed, encoding_table

When to use each

Use Number Base Converter when…

Binary to Decimal Converter

Convert binary (base 2) number to decimal

Hex to Decimal Converter

Convert hexadecimal to decimal and other bases

Use URL Encoder / Decoder when…

How to encode a URL query parameter value

Safely embed user input or special characters in a URL query string.

How to decode a percent-encoded URL

Convert %XX sequences back to human-readable text for debugging or display.

Frequently asked questions

What is binary (base 2)?: Binary is the native number system of computers. Every integer is represented using only the digits 0 and 1. Each digit position represents a power of 2: the rightmost is 2^0 (1), then 2^1 (2), 2^2 (4), 2^3 (8), and so on. The decimal number 10 is 1010 in binary (8 + 2).
What is hexadecimal (base 16) and why do developers use it?: Hexadecimal uses 16 digits: 0–9 and A–F. Developers prefer hex because it maps cleanly to binary: each hex digit represents exactly 4 binary digits (a nibble). This makes hex a compact way to express binary values — the 8-bit byte 11111111 is simply FF in hex, and 32-bit memory addresses fit in 8 hex characters. CSS color values (#FF6600), file magic bytes, and network masks are all commonly expressed in hex.
What is the difference between encodeURI and encodeURIComponent?: encodeURI is designed for complete URLs — it leaves the structural characters (: / ? # & = + @) untouched so the URL remains valid. encodeURIComponent is designed for individual values within a URL — it encodes those structural characters too, preventing them from being misinterpreted as URL delimiters. Use encodeURIComponent for query parameter values; use encodeURI only if you have a full URL that you want to sanitise without breaking its structure.
Why does a space sometimes appear as + instead of %20?: HTML forms using application/x-www-form-urlencoded encoding replace spaces with + rather than %20. Both are valid in query strings, but they are different encodings. Modern APIs and URLs use %20 (RFC 3986). If you are constructing a query string for a form submission, check whether the receiving server expects + or %20.