Free browser-based binary converter

ASCII to Binary Converter

Convert ASCII text into fixed 8-bit binary groups instantly. Use UTF-8 Bytes when your text includes accents, non-Latin scripts, symbols, or emoji.

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Convert ASCII characters to binary

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ASCII mode emits one 8-bit group per character and marks unsupported characters instead of guessing an encoding.

ASCII input Enter ASCII text, or switch to UTF-8 Bytes for multilingual text. Binary output 0 characters

Conversion guide

How to Convert ASCII to Binary

Each ASCII character has a decimal value from 0 to 127. To convert a character to binary, look up its ASCII value, write that number in base 2, and pad the result to eight digits. The capital letter A is decimal 65, so its 8-bit form is 01000001.

The default tool repeats this process for every character, including spaces and control characters. For example, Hi becomes 01001000 01101001. Space-separated output is easiest to inspect because every 8-bit group maps to one ASCII character.

Character	ASCII decimal	8-bit binary
A	`65`	`01000001`
B	`66`	`01000010`
a	`97`	`01100001`
0	`48`	`00110000`
Space	`32`	`00100000`

ASCII to Binary in JavaScript

JavaScript can read each ASCII character with charCodeAt, convert the decimal value with toString(2), and use padStart(8, "0") to produce a full byte. Validate values above 127 before calling the result ASCII.

function asciiToBinary(text) {
  return Array.from(text, (character) => {
    const value = character.charCodeAt(0);
    if (value > 127) throw new Error("Non-ASCII character");
    return value.toString(2).padStart(8, "0");
  }).join(" ");
}

asciiToBinary("Hi");
// 01001000 01101001

ASCII to Binary in Python

Python's ord function returns the numeric value of a character, and format(value, "08b") writes that value as an 8-bit binary string. Checking that every value is below 128 keeps the conversion strictly ASCII.

def ascii_to_binary(text):
    if any(ord(char) > 127 for char in text):
        raise ValueError("Non-ASCII character")
    return " ".join(format(ord(char), "08b") for char in text)

print(ascii_to_binary("Hi"))
# 01001000 01101001

7-bit ASCII vs 8-bit Binary

Standard ASCII needs only seven bits because its highest value is 127, or 1111111. Computers normally store data in 8-bit bytes, so converters add a leading zero. That is why ASCII A is often shown as 01000001 instead of 1000001.

The leading zero does not change the value. It creates a consistent byte-sized result that is easier to group, transmit, compare, and convert back to text.

One ASCII character equals one 8-bit group here.

This rule is reliable only for standard ASCII. Characters outside U+007F need a named encoding such as UTF-8.

ASCII Binary vs UTF-8 Binary

ASCII is a subset of UTF-8, so English letters, digits, punctuation, and control characters have the same single-byte values in both. Non-ASCII characters are different. The character é is not standard ASCII; in UTF-8 it uses two bytes: 11000011 10101001.

Writing é as 11101001 assumes a single-byte encoding such as Latin-1, not ASCII or UTF-8. Use the UTF-8 Bytes mode when your input includes accents, Chinese, Japanese, emoji, or any other character above U+007F.