Base Converter

How to use it

1. Type the value to convert - letters A to Z are digits from 10 to 35, case does not matter.
2. Pick the source base from the dropdown; common bases 2, 8, 10 and 16 are labeled.
3. Binary, octal, decimal and hexadecimal results all update as you type.
4. Invalid characters for the chosen base are reported with the exact position.
5. Spaces and underscores inside the value are ignored, so 1_0000 is fine.

Common use cases

• Programming and debugging - check what a hex constant looks like in binary before using it.
• Networking - convert subnet values between dotted decimal, hex and binary views.
• Education - explore how the same number reads in base 2, 8, 10, 16 or any base up to 36.
• Data formats - decode IDs and colors that appear in a different base than expected.

Why it stays private

The conversion is digit-by-digit arithmetic with arbitrary-precision integers inside the page. Nothing is uploaded, nothing is stored, and the page makes no network requests after it loads.

FAQ

Q: How large a number can it convert? A: Effectively unbounded. Parsing uses arbitrary-precision integers, so even numbers with hundreds of digits keep exact results - only display width becomes the limit.

Q: Can it convert negative numbers or fractions? A: No. It handles non-negative integers only. For fractions, convert the integer and fractional parts separately with a tool that supports fractional bases.

Q: Why is my base-10 input rejected in base 16 mode? A: It is probably the other way around - a digit like 8 or 9 is fine in decimal but a value like 1G contains G, which only exists from base 17 up. Check the reported position in the error message.