Number Base Converter — Binary, Octal, Decimal, Hex Online Free
Convert numbers between binary, octal, decimal, and hex with live output, bit-level views, signed/unsigned interpretations, and ASCII lookup — all in your browser.
Also searched as: number base converter · binary to decimal · hex to decimal · octal converter · base conversion online
Converted values
Bit representation
| Width | Binary | Unsigned | Signed |
|---|---|---|---|
| 8-bit | 11111111 | 255 | -1 |
| 16-bit | 0000000011111111 | 255 | 255 |
| 32-bit | 00000000000000000000000011111111 | 255 | 255 |
ASCII lookup
Type a character to see its numeric code in decimal, hex, and binary.
How to Use
Step-by-step guide to get the most from this tool
- 1
Enter a number
Type a value in the input field.
- 2
Select input base
Choose a preset (2, 8, 10, 16) or enter a custom base from 2–36.
- 3
Read live outputs
Binary, octal, decimal, and hex update as you type — copy any row.
- 4
Inspect bits or ASCII
Use the bit panel for nibble/byte views, or the ASCII lookup for character codes.
Features
What makes this tool stand out
Bases 2–36
Presets plus custom input base.
Live conversion
Outputs update as you type.
Bit panel
Nibbles, bytes, signed/unsigned 8/16/32-bit.
ASCII lookup
Character to decimal, hex, and binary.
One-click copy
Copy any converted value.
Private
100% client-side — no network calls.
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Frequently Asked Questions
Quick answers to common questions
What number bases are supported?+
Binary (2), octal (8), decimal (10), hexadecimal (16), and any custom base from 2 to 36.
How do I convert binary to decimal?+
Enter your binary number, select base 2 as the input base, and read the decimal output row instantly.
What characters are valid in hexadecimal?+
Digits 0–9 and letters A–F (case insensitive). For bases above 16, letters extend through Z.
Can I convert negative numbers?+
Yes. Enter a leading minus sign. The bit panel shows signed and unsigned interpretations for 8, 16, and 32 bits.
Is there a size limit?+
JavaScript safely represents integers up to Number.MAX_SAFE_INTEGER (2^53 − 1). Larger values may lose precision.
Is my data sent to a server?+
No. All conversion uses native parseInt and toString in your browser.