Number Base Converter
Convert any number between binary, decimal, hexadecimal and octal. Enter a value, pick its base, and see all four at once.
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Convert Numbers Between Any Base
Computers count in more than one number system. This free number base converter turns a value between binary (base 2), decimal (base 10), hexadecimal (base 16), and octal (base 8). Type a number, tell it which base you entered, and see all four at once.
Programmers use it to read memory addresses, color codes, and bit flags, where hex and binary show up constantly. Students use it to check base-conversion homework. It runs in your browser and validates your digits so you never get a wrong answer from a typo.
How to Use the Number Base Converter
- 1Type your number into the box.
- 2Choose which base you entered it in.
- 3Click Convert to see the value in binary, decimal, hex and octal.
Why Use MakeToolz's Number Base Converter?
Four bases
Binary, decimal, hexadecimal and octal, all shown together.
Input validation
Checks your digits match the base you picked, so a typo cannot give a wrong result.
Accepts prefixes
Paste 0x or 0b prefixed values and it strips them automatically.
Instant
Conversion is immediate, right in your browser.
Private
Nothing you enter is uploaded.
Free
No signup, no limits.
Why Computers Use More Than One Base
A number base is just how many digits a system counts with before it rolls over. Decimal, base 10, uses ten digits because people have ten fingers. Computers store everything as on-or-off switches, so they naturally count in binary, base 2, with only 0 and 1. Binary is exact for machines but long and hard for people to read, so programmers lean on hexadecimal, base 16, as a compact shorthand. Octal, base 8, is an older shorthand still seen in file permissions.
The same quantity looks different in each base but never changes value. The number ten is 1010 in binary, 12 in octal, and A in hex. This converter shows all four at once so you can move between them without arithmetic.
Who Converts Between Bases and When
Programmers convert when reading memory addresses, byte values, and bit flags, which almost always appear in hex. Web developers meet hex in color codes, where two hex digits set one color channel. Network engineers read binary to work out subnet masks. Computer science students convert by hand for homework and use a tool to check the answer.
The pattern is any task where a value must be understood in the base a system actually uses, then translated to one people can read.
The Same Numbers in Four Bases
| Decimal | Binary | Octal | Hexadecimal |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 8 | 1000 | 10 | 8 |
| 10 | 1010 | 12 | A |
| 15 | 1111 | 17 | F |
| 16 | 10000 | 20 | 10 |
| 255 | 11111111 | 377 | FF |
How the Conversion Works
Every base works by place value. In decimal, each spot is a power of ten. In binary, each spot is a power of two, so the digits of 1010 stand for eight, zero, two, and zero, which add to ten. To convert, the tool reads your digits in the base you chose, works out the plain value, then rewrites that value in each of the other bases. Because two hex digits equal exactly eight binary digits, or one byte, hex and binary line up cleanly, which is why hex is the go-to shorthand for raw data.
Benefits and Limits
The benefit is speed and accuracy. Converting long binary strings by hand invites errors, and the tool removes them while showing all four bases together for easy comparison. It also strips 0x and 0b prefixes so you can paste code values directly.
The limit is size. Very large numbers can exceed what a browser can hold precisely, so results for huge values may lose the last few digits. For everyday work with addresses, colors, and byte-sized data, the answers are exact. If you are decoding raw binary text rather than a number, a Base64 encoder and decoder is the better fit.
Common Mistakes and Tips
The most frequent mistake is entering digits that do not belong to the base. Binary allows only 0 and 1, and octal only 0 through 7, so a stray 2 or 8 makes the value invalid. This tool flags mismatched digits before converting.
Another error is forgetting that hex uses letters A to F for the values ten to fifteen. A hex F is not fifteen tens; it is a single digit worth fifteen.
A useful tip: to read a hex color, split it into pairs and convert each pair to decimal to get the red, green, and blue values, then a HEX to RGB converter confirms the result at a glance.
People Also Ask
How do I convert binary to decimal?
Enter the binary digits, choose Binary, and read the decimal result. Each position is a power of two, so 1010 works out to eight plus two, which is ten.
Why do programmers use hexadecimal?
Hex is a compact way to write binary. Two hex digits equal one byte of eight bits, so long binary values shrink to short, readable codes for addresses, colors, and data.
What is base 2 versus base 16?
Base 2, binary, counts with two digits, 0 and 1, the way computers store data. Base 16, hex, counts with sixteen digits, 0 to 9 then A to F, and packs four binary digits into one.
How many binary digits are in one hex digit?
Exactly four. That clean fit is why hex is the standard shorthand for binary, since eight binary digits collapse neatly into two hex characters.
What does the 0x prefix mean?
The 0x prefix marks a number as hexadecimal in many programming languages. It is not part of the value, so this tool strips it before converting. A 0b prefix marks binary the same way.
Can I convert decimal to octal here?
Yes. Enter your decimal number, choose Decimal, and the octal result appears alongside binary and hex. Octal shows up in Unix file permissions.
Why is my octal number invalid?
Octal uses only the digits 0 through 7. If you typed an 8 or 9, it does not belong to base 8, so the tool asks you to check the digits.
Frequently Asked Questions
How do I convert binary to decimal?
What is hexadecimal used for?
Why does my binary number fail?
Is there a size limit?
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