Base Converter
Convert between binary, octal, decimal, hexadecimal, and any base from 2 to 36
Features
Display 4 major bases at a glance
Show results in binary, octal, decimal, and hexadecimal side by side as you type
Freely specify bases 2–36
Choose the input base and any additional bases to display from 2 to 36
Handle multiple values and large integers
Convert multiple inputs at once with delimiters, no rounding errors for negative or multi-digit numbers
Adjust notation for code
Toggle uppercase/lowercase letters and 0b, 0o, 0x prefixes
How to Use
Select the input base
Choose the base of your input value from 2 to 36 in "Input base" (default is decimal)
Enter the integer to convert
Type an integer in the input field. Separate multiple values with line breaks, commas, or spaces to convert them together
Adjust display and notation
If needed, change "Additional bases to display", letter case, and prefix options
Copy the result you need
Select the base you want from the results listed for each value and click the copy button
Use Cases
Check flag values and addresses
Convert hexadecimal flag values or memory addresses to decimal or binary to verify program behavior
Verify base conversion answers
Check multiple base conversion problems from exams or coursework against correct answers
Check IP address bits
Display each octet of a subnet mask or IP address in binary to verify network settings
Convert base-36 IDs
Cross-reference base-36 IDs with their decimal equivalents to verify data
Knowledge Base
What is radix (base)?
Radix is the number of different digits used in a numeral system. In base N, you use N different digits (0 through N−1), and each position is worth N times more than the position to its right. For example, decimal 255 is 11111111 in binary and FF in hexadecimal.
- Why base 36 is the limit：To represent values 10 and above with single digits, letters A–Z are assigned in order. Since you have 10 digits and 26 letters, base 36 (where Z represents 35) is the standard upper limit.
Meaning of 0b, 0o, 0x prefixes
0b, 0o, and 0x are symbols placed at the start of numbers in programming languages to indicate which base the number is written in.
- 0b (binary)：0b is a prefix derived from "binary" and indicates base 2. For example, 0b1010 represents decimal 10.
- 0o (octal)：0o is a prefix derived from "octal" and indicates base 8. For example, 0o17 represents decimal 15.
- 0x (hexadecimal)：0x is a prefix derived from "hexadecimal" and indicates base 16. For example, 0xFF represents decimal 255.
Representing negative numbers
Negative numbers can be represented in two ways: signed notation with a minus sign prefix, or two's complement notation within a fixed number of bits.
- Signed notation：In signed notation, negative numbers are written with a minus sign followed by the positive representation. For example, −255 is written as −11111111 in binary and −FF in hexadecimal.
- Two's complement：Two's complement is how computers represent negative numbers internally. In 8-bit two's complement, −1 is represented as 11111111, which differs from signed notation despite using the same bit pattern.
Safety and Privacy
Runs entirely in your browser
Your input data is processed only within your browser and is never sent externally.
Processing only in your browser
Conversion processing is processed entirely within your browser, and input data is not sent to any server.
Communications encrypted with HTTPS
Page loading is also encrypted by TLS, and content cannot be read by third parties.
No transmission to third parties
Input content is not sent to external services such as ad networks or trackers.
Input numbers are not saved
Only settings are saved locally in your browser. Input numbers are excluded from saving.
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Updates
- update #384
New tool added: convert integers between bases 2–36 in a comprehensive list
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