Binary, Decimal & Hex Converter
Convert between binary, octal, decimal, hexadecimal and any base.
Arbitrary base (2–36)
| Decimal | Binary | Octal | Hexadecimal |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 1 | 1 | 1 | 1 |
| 2 | 10 | 2 | 2 |
| 3 | 11 | 3 | 3 |
| 4 | 100 | 4 | 4 |
| 5 | 101 | 5 | 5 |
| 6 | 110 | 6 | 6 |
| 7 | 111 | 7 | 7 |
| 8 | 1000 | 10 | 8 |
| 9 | 1001 | 11 | 9 |
| 10 | 1010 | 12 | A |
| 11 | 1011 | 13 | B |
| 12 | 1100 | 14 | C |
| 13 | 1101 | 15 | D |
| 14 | 1110 | 16 | E |
| 15 | 1111 | 17 | F |
| 16 | 10000 | 20 | 10 |
How do you convert a number between binary, decimal and hexadecimal?
To convert a number between bases, you first expand it in decimal using each digit's positional value, then repeatedly divide by the target base to read off the new digits from the remainders. Docuboxer's number base converter does this instantly: type into any of the four fields — binary, octal, decimal or hexadecimal — and the other three update live, with per-field validation that flags exactly which digit isn't valid for that base, like a stray "2" in binary or a "G" in hex. It handles negative numbers and arbitrarily large integers using BigInt, so a 64-character SHA-256 hash or any huge value converts without losing a single digit — something JavaScript's regular Number type can't guarantee past 2^53. There's also an arbitrary base section (2 to 36) and a quick reference table. Everything runs locally in your browser, free, with no signup and no size limit.
How to use Binary, Decimal & Hex Converter
- Type your number into whichever field matches its current base — binary, octal, decimal or hexadecimal.
- The other three fields update automatically, converted to the same value in their own base.
- For any base outside the standard four, use the arbitrary base section: pick a source base and a target base between 2 and 36.
- Copy the value you need with the copy button next to each field.
- Turn on "group in nibbles" to read long binary numbers more easily, four bits at a time.
Common use cases
Debugging color values and bitmasks
Convert a hex color code to binary to see exactly which bits a mask is switching, or turn a decimal RGB value into hex without doing the math by hand.
Checking hashes and checksums
Convert a SHA-256 or MD5 hash from hex to decimal to compare values or paste it into a system that only accepts integers — BigInt means no rounding risk on long hashes.
Reading Unix file permissions
Translate an octal permission value like 755 into binary to see exactly which combination of read, write and execute each digit represents.
Learning number systems
Watch the conversion method play out step by step as you type — useful for computer science coursework or brushing up before a technical interview.
Embedded programming and hardware registers
Convert register values or memory addresses between hex and binary to make sense of datasheets and microcontroller documentation.
Frequently asked questions
How do you convert decimal to binary?
Divide the number by 2 repeatedly, keeping track of each remainder. Reading the remainders from bottom to top gives you the binary number. This tool automates that the moment you type a value into the decimal field.
How do you convert hex to decimal?
Multiply each hex digit by 16 raised to its position (counting from 0 on the right) and add the results. For example, FF = 15×16¹ + 15×16⁰ = 255.
Why doesn't this converter lose precision on large numbers?
It uses BigInt instead of JavaScript's Number type. Number loses precision past 2^53, which would corrupt conversions of long hashes or huge integers; BigInt has no such ceiling.
Can I convert negative numbers?
Yes. Put a minus sign in front of the value in any of the four fields, and the sign carries through correctly to every other base.
What do the 0x, 0b and 0o prefixes mean?
They're standard programming prefixes: 0x for hexadecimal, 0b for binary and 0o for octal. Paste them straight into the matching field and the tool recognizes and strips them automatically.
Can I convert to a base other than binary, octal, decimal or hex?
Yes — the arbitrary base section lets you pick any base from 2 to 36, handy for things like encoding short identifiers in base 36.