Number Base Converter
Convert numbers instantly between binary, decimal, octal, hexadecimal and any base from 2 to 36. Fully usable on mobile.
How to Use the Number Base Converter
From typing a number to every base at once, in seconds. Fully usable on mobile.
Every conversion runs inside your own browser. No account, no tracking, nothing ever uploaded.
Number Base Converter, Free and Online
A number base converter rewrites a number from one numeral system into another, binary, octal, decimal, hexadecimal or any base from 2 to 36, without changing the underlying value it represents. This one shows every common base at once, updates as you type, and runs entirely inside your browser.
Whether you are learning binary for the first time, checking a hexadecimal color code, or working through a computer science assignment, a reliable number base converter should show more than one answer at a time. Type a number, pick the base it is currently in, and this tool instantly displays the binary, octal, decimal and hexadecimal equivalents side by side, each with a one tap copy button. Pro Mode adds a live custom base slider covering every base from 2 to 36, fractional number conversion for values with a decimal point, a full bitwise operations calculator (AND, OR, XOR, NOT, and bit shifts), step by step working showing the division method, and a CSV export listing every base from 2 through 36 at once.
Every conversion passes through decimal as a common middle step. This calculator reads your number in its original base, converts it to decimal internally, then converts that decimal value into whichever bases you need, keeping every result exact.
1Simple vs Pro, What Each Mode Includes
| Feature | Simple Mode | Pro Mode (Free) |
|---|---|---|
| Binary, octal, decimal and hexadecimal, shown together | Included | Included |
| Convert from bases 2, 8, 10, 16 or 36 | Included | Included |
| Custom base slider, any base 2 to 36 | Not included | Included |
| Fractional number conversion | Not included | Included |
| Bitwise operations (AND, OR, XOR, NOT, shifts) | Not included | Included |
| Step by step working, CSV export of all bases 2 to 36 | Not included | Included |
2Common Number Bases, Quick Reference
The mistake that trips up the most students converting binary to decimal by hand, or the reverse, is losing track of place value once the number gets longer than a few digits. Every digit in a positional number system is multiplied by the base raised to a power based on its position, counting from zero on the right, and a single missed power of the base throws off the entire result. This calculator avoids that entirely by working with exact integer arithmetic internally, which also means it handles very large numbers correctly, a common weak point in simpler converters that switch to floating point and quietly lose precision on long binary or hexadecimal strings.
3Where Binary Actually Came From
Every binary digit typed into a base converter today traces back to a German polymath who was more interested in philosophy than computers. According to MIT Press, in their scholarly edition of Leibniz's writings on the subject, Gottfried Wilhelm Leibniz worked out the binary number system in manuscripts written around 1679, using only the digits 0 and 1, but did not publish a formal account until 1703. What makes that publication genuinely unusual is its full title, which explicitly connects binary arithmetic to the ancient Chinese hexagram figures attributed to Fuxi, since Leibniz had noticed that the I Ching's yin and yang symbols formed patterns strikingly similar to his own binary progression. Leibniz had no digital computer to apply the system to, that would wait more than two centuries, yet the same base 2 logic he described is exactly what this calculator converts to and from today.
| Question | Quick Answer |
|---|---|
| Who developed the modern binary number system? | Gottfried Wilhelm Leibniz |
| When did he first work it out? | Around 1679 |
| When was it formally published? | 1703 |
| What surprising connection did his paper make? | Ancient Chinese I Ching hexagram figures |
Every conversion runs inside your own browser using JavaScript, nothing is uploaded or sent to a server, and no account or signup is required.
4Frequently Asked Questions
Grounded in MIT Press's scholarly edition of Leibniz's original writings on binary arithmetic, not the assumption that binary was invented for computers. The full account is available via MIT Press. For related tools on this site, see the Scientific Calculator and the full SmallStudyTools.com tool library.
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