Number System Converter

How to use the Number System Converter

1. Type the number in the Number box.
2. Choose its base in From, such as Decimal (base 10).
3. Choose the base you want in To, such as Binary (base 2).
4. Read or copy the result; the table below shows binary, octal, decimal and hex together.

Features

• Any base from 2 to 36, with binary, octal, decimal and hex listed first
• Exact results for numbers of any size (BigInt arithmetic)
• Negative numbers supported
• Accepts 0b/0o/0x prefixes, spaces and underscores
• Clear message naming the invalid digit
• Binary grouped in 4-bit nibbles; copy buttons for every base

Frequently asked questions

How do I convert binary to decimal?

Multiply each bit by its power of two and add them. For example, 1011 = 8 + 0 + 2 + 1 = 11. Choose Binary in From and Decimal in To to do it automatically.

How do I convert decimal to hexadecimal?

Divide by 16 repeatedly and read the remainders backwards, using A–F for 10–15. For example, 255 is FF in hexadecimal.

Can it convert very large numbers?

Yes. It uses arbitrary-precision integers, so values beyond 2^53, such as 18446744073709551615 (FFFFFFFFFFFFFFFF), convert exactly.

Does it support fractions or two’s complement?

Not yet. It converts whole numbers and shows negative values with a minus sign rather than a fixed-width two’s complement pattern.

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