Converters
Number Base Converter
Binary, octal, decimal, and hexadecimal, together.
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CalcoTools · Number Base Converter · generated 8/23/2026, 1:05:11 PM
About the Number Base Converter
Converts a number between binary, octal, decimal, and hexadecimal at once, showing all four representations of the same value side by side.
How to use it
- Enter a Value.
- Select which Base that value is currently in.
- Read all four base representations in the readout.
Formula
Each digit position represents a power of the base: for base b, the digit at position i contributes digit × b^i. Converting re-expresses the same value in a different positional system.
Worked example
Decimal 255 is 11111111 in binary, 377 in octal, and FF in hexadecimal — all four represent the identical quantity.
Recommendations
- • Hexadecimal is common in programming for colors, memory addresses, and byte values, since two hex digits map cleanly to one byte.
- • Binary digits group naturally into sets of 4, which is exactly one hex digit — handy for mental conversion between the two.
- • Entering digits invalid for the selected base, like an 8 while in binary, will be flagged as invalid.
Frequently asked questions
Hexadecimal is base 16, which needs 16 distinct digits — after 0-9, it continues with A-F to represent values 10 through 15.