Decimal to Binary Converter

What is the Decimal to Binary Converter?

This tool converts decimal numbers (base-10) to binary numbers (base-2), showing how the numbers we use every day are represented in computer memory.

How it works: repeatedly divide by 2 and collect the remainders. Read the remainders from bottom to top to get the binary value.

Why Convert Decimal to Binary?

Programming Fundamentals

Understand how data types and numbers are stored under the hood.

Bitwise Operations

Work confidently with AND, OR, XOR, and bit shifts.

Network Settings

IP addresses and subnet masks are defined in binary.

File Sizes

Bytes, kilobytes, and megabytes build on powers of 2.

The Conversion Method

Divide by 2 repeatedly and record each remainder, then read the remainders from bottom to top.

Example: 10 ÷ 2 = 5 r0, 5 ÷ 2 = 2 r1, 2 ÷ 2 = 1 r0, 1 ÷ 2 = 0 r1 → 1010.

How to Use

Enter the Decimal Number

Type any positive integer using the digits 0–9.

View the Binary Result

The conversion happens automatically and appears in the second field as you type.

Copy the Result

Click the copy button to use the binary value elsewhere.

Bidirectional: both fields are editable. Type a binary value in the result field to convert it back to decimal, or use the swap button to flip the direction.

Common Decimal to Binary Values

Decimal	Binary	Meaning
15	`1111`	nibble maximum
255	`11111111`	byte maximum
1024	`10000000000`	1 KB (2¹⁰)

Readability: binary results are grouped in sets of 4 digits, so 11110000 displays as 1111 0000.

Frequently Asked Questions

Can I enter decimals or negative numbers?

This converter is designed for positive integers, the most common case for learning and programming. Enter a whole number to get its binary representation.

Why is the result grouped into fours?

Grouping bits into nibbles (sets of 4) makes long binary strings far easier to read, and each nibble maps neatly to one hexadecimal digit.

Why does 255 become 11111111?

255 is the largest value an 8-bit byte can hold: 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255, so all eight bits are set to 1.

How do I convert binary back to decimal?

Type a binary number directly into the result field, or press the swap button to reverse the direction of the conversion.

Decimal to Binary