🔣 Number Base Converter

What This Tool Does

This tool converts numbers between different bases — decimal, binary, hexadecimal, and octal. Enter a number in any base and it shows the equivalents in the others. It is an everyday helper for programmers, students, and anyone working close to how computers represent numbers, turning the awkward arithmetic of base conversion into an instant, reliable result.

We count in decimal (base 10), but computers work in binary (base 2), and programmers frequently use hexadecimal (base 16) as a compact way to write binary. Converting between these by hand is slow and error-prone, so a converter that handles all the common bases at once is a genuine time-saver whenever you work with them.

How Number Bases Work

A number base determines how many digits are used and what each position is worth. Decimal (base 10) uses digits 0–9, and each position is worth ten times the one to its right. Binary (base 2) uses only 0 and 1, with each position worth twice the previous — this matches the on/off nature of computer circuits. Hexadecimal (base 16) uses 0–9 plus A–F (where A is 10, up to F is 15), and octal (base 8) uses digits 0–7.

The reason hexadecimal is so popular with programmers is that it maps neatly onto binary: each hex digit represents exactly four binary digits, so a long string of ones and zeros becomes a short, readable hex value. The number 255, for instance, is 11111111 in binary but just FF in hex. This compactness, while staying tied to the underlying binary, is why hex appears throughout computing — in color codes, memory addresses, and low-level data. The converter handles the math between all these representations so you can move between them effortlessly.

Quick Tips

• Each hexadecimal digit represents exactly four binary digits, which is why hex is a compact way to write binary.
• Hex uses A–F for the values 10 through 15, so FF is 255.
• Binary uses only 0 and 1, matching the on/off states of computer circuits.
• Convert rather than calculating by hand — a small slip in a base value can cause real bugs.

Frequently Asked Questions

What is a number base?

It is the number of distinct digits a system uses and how much each position is worth. Decimal (base 10) uses 0–9, binary (base 2) uses 0–1, hexadecimal (base 16) uses 0–9 and A–F, and octal (base 8) uses 0–7.

Why do programmers use hexadecimal?

Because each hex digit maps to exactly four binary digits, hex is a compact, readable way to write binary values. A long binary string becomes a short hex value, which is easier to work with while staying tied to the underlying binary.

What is 255 in binary and hex?

255 is 11111111 in binary (eight ones) and FF in hexadecimal. This is why a single byte holds values from 0 to 255 and why hex is so convenient for representing bytes.

Is my data private?

Yes. All conversion happens in your browser, so nothing you enter is uploaded or stored. You can convert values safely.