Binary, Octal, Decimal, Hex Converter
Updated September 2026
Convert a number between binary, octal, decimal, and hexadecimal instantly. Enter a value, pick its source base, and see all four conversions at once — free.
Verified Capabilities
Converts one entered number to Binary, Octal, Decimal, and Hexadecimal simultaneously.
Hexadecimal letters A–F are accepted in either uppercase or lowercase.
Select the source base, enter the number, and get all four results in a single click.
Only bases 2, 8, 10, and 16 are supported — no custom base — and it does not update all four fields live as you type in any one of them, only via the Convert button.
Whether you're planning finances, comparing options, or verifying numbers, having an accurate calculator ready saves time and prevents costly mistakes.
Convert a number between binary, octal, decimal, and hexadecimal instantly. Enter a value, pick its source base, and see all four conversions at once — free. Results are immediate — no waiting, no loading screens, no account required.
Who uses the Number Base Converter?
- Computer science students learning number systems and digital logic fundamentals.
- Programmers converting memory addresses and bitfield masks during debugging.
- Embedded engineers converting sensor values between decimal and hex registers.
Common uses and search terms
The Number Base Converter is frequently used for: binary, hex, octal, base conversion, hexadecimal converter, number system converter. Whether you need a quick result or are working through a longer project, the tool handles all common variations without any configuration.
Accuracy and formula transparency
The Number Base Converter uses a validated formula consistent with published standards from recognised financial and mathematical authorities. All arithmetic is performed with 64-bit IEEE 754 floating-point precision — the same standard used by Microsoft Excel, Google Sheets, and professional financial software. Rounding, if applied, follows standard half-up convention unless stated otherwise. Inputs and results are processed entirely in your browser; no data is transmitted to any server. For consequential financial or legal decisions, always verify results with a qualified professional.
Why use Allio Tools's Number Base Converter?
Everything runs locally in your browser. No data is sent to a server, logged, or stored anywhere. The tool is completely free with no usage limits, no premium tiers, and no account required. Available in 11 languages and optimised for all screen sizes, the Number Base Converter works on desktop, tablet, and mobile with no app download needed.
See also:Mortgage Calculator · Currency Converter · Loan Calculator
How the Number Base Converter works
Enter your number in the Number field.
Select the base your number is currently in from the Source Base dropdown: Decimal, Binary, Octal, or Hexadecimal.
Click Convert to see the equivalent value in all four bases (Binary, Octal, Decimal, Hexadecimal) at once.
For hexadecimal numbers, letters A–F work in either uppercase or lowercase.
Tips & tricks
- This is a one-way convert: enter a number, pick its source base, click Convert — it doesn't update all four fields live as you type into any one of them.
- All four output bases (Binary, Octal, Decimal, Hexadecimal) are shown together every time, regardless of which source base you picked.
- Only bases 2, 8, 10, and 16 are supported — there's no arbitrary custom-base (e.g. base 36) input.
- Negative numbers aren't accepted — enter the absolute value if you need to convert a negative number's magnitude.
Popular Number Base Converter Conversions
Frequently Asked Questions
How do I convert decimal to binary?
Repeatedly divide by 2 and record remainders from bottom to top. For example, 13 → 1101 in binary. Select Decimal as the source base, enter 13, and the converter shows the binary result instantly along with octal and hex.
What is hexadecimal used for?
Hexadecimal (base 16) is used in programming, web colors (e.g. #FF5733), memory addresses, and machine code. It compresses binary data — each hex digit represents exactly 4 binary bits.
What is the maximum number I can convert?
The tool handles numbers up to JavaScript's safe integer range (2^53, about 9 quadrillion). For larger numbers, use a dedicated big-integer library.
Can I convert negative numbers?
No — the tool only accepts unsigned positive integers (0 and above); a negative value returns an error. Negative numbers in computing use two's complement representation, which depends on word size and isn't handled here.
Can I convert to or from a custom base like base 36?
No — the Source Base dropdown only offers Decimal, Binary, Octal, and Hexadecimal (bases 10, 2, 8, and 16). Other bases aren't supported.
How do I convert hex color codes to RGB?
Split the 6-digit hex into pairs: #FF5733 → FF, 57, 33 → convert each pair from hex to decimal → R=255, G=87, B=51. You can convert each pair here with Hexadecimal as the source base, or use the color converter tool for a dedicated color workflow.
What formats does the Number Base Converter support?
The Number Base Converter converts between binary, decimal, hexadecimal, hex, and more. All conversions work in both directions — instantly, with no sign-up required.
Is my data safe when using the Number Base Converter?
Completely safe. The Number Base Converter processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.
How accurate are the Number Base Converter results?
The Number Base Converter uses standard, well-established mathematical formulas used by professionals worldwide — the same ones used by banks, financial advisors, and accounting software. Results are as accurate as the inputs you provide. See our <a href="/methodology/">Methodology page</a> for formula sources and references. For financial decisions, always verify with a qualified professional.
Can I share the Number Base Converter results with someone?
Yes. Copy the result number or screenshot the page to share via message, email, or social media. You can also bookmark and share the tool URL directly — the Number Base Converter opens instantly for anyone with a modern browser, no account needed.
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