A number base defines the digits and place values used to represent a value. Common systems include binary base 2, octal base 8, decimal base 10, and hexadecimal base 16. Each system shows the same value differently.
A Number Base Converter changes a value from one numeral system to another. It helps developers convert binary, octal, decimal, hexadecimal, and ASCII values for code, testing, data, and debugging tasks.
Use our Number Base Converter to change values between binary, octal, decimal, hexadecimal, and ASCII. Enter a value, choose the input base, then copy the converted result for your work.
Type or paste the number you want to convert
Select binary, octal, decimal, hexadecimal, or ASCII as the input base.
Copy your converted number for future use.
Type or paste the number you want to convert
Select binary, octal, decimal, hexadecimal, or ASCII as the input base.
Copy your converted number for future use.
Toolsweb Number Base Converter gives fast conversion between common systems. It keeps input clear, results simple, and copying easy.
Convert common values between binary, octal, decimal, and hexadecimal number systems with one tool.
Turn ASCII characters into numeric codes and numeric codes back into readable characters for simple text and character checks.
Get converted values immediately after entering valid input and selecting the correct base.
Enter a value and choose its source and target format through clear input and output fields.
Copy converted results with one click for code, notes, documentation, testing, or repeated number base checks.
Use the Number Base Converter online without paying for basic number base conversion features in your browser.
Number base conversion changes how a value looks without changing its value. These common systems use different digits and place values.
Binary uses only 0 and 1. Each position represents a power of two, making it useful for computer data. Developers use binary when working with bits.
Octal uses digits from 0 through 7. It offers a shorter way to group binary values in some systems. Three binary bits map to one octal digit.
Decimal uses digits from 0 through 9. People use it as the standard base for everyday counting. Each position represents a power of ten.
Hexadecimal uses 0 through 9 and A through F. One hex digit represents four binary bits, so hexadecimal gives developers a compact view of binary data.
ASCII maps common characters to numeric codes. This helps developers view text as values during coding. For example, uppercase A uses decimal code 65.
Convert between number bases with place values or repeated division. The steps below cover common conversions used by developers.
Divide a decimal number by 2 repeatedly. Read the remainders from bottom to top to get the binary value. For example, decimal 10 becomes binary 1010.
Divide the decimal number by 8 repeatedly. Read the remainders from bottom to top for the octal result. For example, decimal 64 becomes octal 100.
Divide the decimal number by 16 repeatedly. Replace values from 10 to 15 with A through F. For example, decimal 255 becomes hexadecimal FF.
Multiply each binary digit by its power of 2, then add the results to get the decimal value. For example, 1010 equals 10 in decimal.
Group binary digits into sets of four, then map each group to a hexadecimal digit from 0 to F. For example, 11111111 becomes FF.
Multiply each hexadecimal digit by its power of 16, then add the results. For example, hexadecimal FF equals 255 in decimal.
Use this quick reference to compare binary base 2, octal base 8, decimal base 10, and hexadecimal base 16.
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Common Number Base Conversion Mistakes
A wrong input base can produce a wrong result even when the digits look valid. Check the source base, allowed digits, signs, and prefixes before converting. Also watch for rounding with very large values, and confirm the output before using it in code or documentation.
These FAQs answer questions about free access, data safety, base conversion, binary, decimal, hexadecimal, octal, and developer use.