Bits and bytes
A bit is a single 0 or 1. A byte is a group of eight bits, and it is the unit text is stored in. The Unicode glossary defines an octet as eight bits taken as one unit, and notes that octet and byte mean the same thing today.[1][2]
Binary text is usually written as bytes with a space between each group of eight, so you can see where one ends and the next begins.
Place values
Each position in a byte is worth twice the one to its right. From left to right the eight places are worth 128, 64, 32, 16, 8, 4, 2 and 1. A 1 means the place counts and a 0 means it does not.
The places work like ones, tens and hundreds in a normal number, only each one doubles instead of growing ten times. That is why eight places are enough for any value from 0 to 255, and why the leftmost place, 128, is worth one more than all seven places to its right added together.
Read a byte in four steps
- Write the byte with its place values above it: 128, 64, 32, 16, 8, 4, 2, 1.
- Add up the place values that sit over a 1.
- The total is the character’s code. For plain English text it will be between 32 and 126.
- Find that code in the ASCII table. 72 is H, 101 is e, and 32 is a space.[3]
Worked example: 01001000
- Binary
- 01001000
- Text
- H
| Place value | Bit | Counts |
|---|---|---|
| 128 | 0 | 0 |
| 64 | 1 | 64 |
| 32 | 0 | 0 |
| 16 | 0 | 0 |
| 8 | 1 | 8 |
| 4 | 0 | 0 |
| 2 | 0 | 0 |
| 1 | 0 | 0 |
- Only the places worth 64 and 8 hold a 1, and 64 + 8 = 72.
- Code 72 in ASCII is capital H.
Worked example: a whole word
- Binary
- 01001111 01001011
- Text
- OK
| Byte | Decimal | Character |
|---|---|---|
| 01001111 | 79 | O |
| 01001011 | 75 | K |
- 01001111 is 64 + 8 + 4 + 2 + 1 = 79, which is O.
- 01001011 is 64 + 8 + 2 + 1 = 75, which is K.
When a byte is not a whole character
In UTF-8, a byte that starts with 0 is one complete character. A byte that starts with 110, 1110 or 11110 begins a longer character, and the bytes after it start with 10. Read those bytes as one group. The page on emoji and accents walks through it.[4][5][6]
Tips for reading faster
- Starts with 010 or 011
- In plain text, a byte starting with 010 is usually a capital letter and one starting with 011 is usually a small letter.
- 00100000 is a space
- Spaces are common in text, so spotting 00100000 shows you where each word ends.
- Digits start with 0011
- The characters 0 to 9 are codes 48 to 57, so their bytes run from 00110000 to 00111001.
Sources, last checked October 12, 2026
- Glossary of Unicode Terms (Unicode Consortium)
An ordered sequence of eight bits considered as a unit.
The Unicode Standard follows current industry practice in referring to an octet as a byte.
The set of 128 Unicode characters from U+0000 to U+007F, including control codes as well as graphic characters.
- RFC 3629: UTF-8, a transformation format of ISO 10646 (IETF, 2003)
The only octet of a "sequence" of one has the higher-order bit set to 0, the remaining 7 bits being used to encode the character number.
In a sequence of n octets, n>1, the initial octet has the n higher-order bits set to 1, followed by a bit set to 0.
The following octet(s) all have the higher-order bit set to 1 and the following bit set to 0, leaving 6 bits in each to contain bits from the character to be encoded.