Free Binary to Decimal Converter Online
Convert binary numbers to decimal instantly in your browser. No uploads needed.
Input
Output
What Is Binary to Decimal Conversion?
Debugging network packets, reading hardware registers, or making sense of permission bits? You need to convert binary to decimal constantly in these situations. This tool handles it: paste one or more binary numbers and get their decimal equivalents instantly. It supports positional notation, optional 0b prefixes, and negative numbers. Each binary digit represents a power of 2 -- for example, 101010 equals 42 in decimal. Built with the browser's native parseInt() function, so your data stays local and conversions are lightning fast. If you need to go the other way, check out our Decimal to Binary converter.
This conversion is essential when reading or debugging low-level computer data, network protocols, or hardware registers. Understanding binary arithmetic is key to working with these systems. This tool converts binary strings to their decimal equivalents instantly, supporting multiple values and optional 0b prefixes.
How to Use This Tool
Enter Binary Numbers
Type or paste one binary number per line in the left editor. Numbers may optionally start with 0b. Click Sample to load examples, or Upload a text file.
View Decimal Output
The right panel updates automatically with the decimal value of each binary number. Invalid binary digits trigger an error message on that line.
Copy or Download
Click Copy to copy the decimal output to your clipboard, or Download to save it as a text file.
Conversion Examples
Here are some common binary to decimal conversions:
Binary Input
Decimal Output
Frequently Asked Questions
How does binary to decimal conversion work?
Each bit position represents a power of 2, starting from the rightmost bit (20 = 1). Multiply each bit by its positional value and sum the results. For example, 101010 = 1×32 + 0×16 + 1×8 + 0×4 + 1×2 + 0×1 = 42. The tool uses JavaScript's parseInt() function with radix 2 under the hood.
Can I convert multiple binary numbers at once?
Yes. Enter one binary number per line in the left editor. The tool converts all of them simultaneously and shows each decimal result on the corresponding line in the right panel.
Does this support the 0b prefix and negative numbers?
Yes to both. The tool automatically strips a leading 0b or 0B prefix. A leading minus sign is preserved (e.g., -101010 becomes -42). See the MDN Number reference for programmatic details.
Is my data private when using this converter?
Absolutely. All processing happens locally in your browser using JavaScript. No data is sent to any server. You can verify this in your browser's Network tab.
What is the maximum binary number length supported?
JavaScript safely handles integers up to 253 - 1 (about 53 binary digits). For numbers larger than that, precision may be lost. For arbitrary precision, consider using BigInt in your code.
Related Tools
Learn more: Britannica on numeral systems, Wolfram MathWorld Binary, and the MDN parseInt documentation.