Decimal ↔ Binary Converter
Free online decimal to binary and binary to decimal converter. Convert numbers between base-10 and base-2 instantly.
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Tip: Type in either field — the other updates automatically. Click ⇄ to swap values.
💡 Definition
Binary Number System
- Binary (base-2) uses only two digits: 0 and 1.
- It is the foundation of all digital computing — every piece of data in a computer is ultimately stored as binary.
- Each binary digit (bit) represents a power of 2.
📖 How to use
Step by Step
- Enter a decimal number on the left
- The binary equivalent appears instantly on the right
- Or enter binary on the right to get decimal
- Click ⇄ to swap the values between fields
🎯 Use cases
When to use
- Understanding how computers store data
- Network subnetting and IP calculations
- Digital electronics and logic gates
- Programming bitwise operations
Frequently Asked Questions
How does decimal to binary conversion work?▾
Repeatedly divide the decimal number by 2 and record remainders. Read the remainders bottom-up. For example: 13 ÷ 2 = 6 R1, 6 ÷ 2 = 3 R0, 3 ÷ 2 = 1 R1, 1 ÷ 2 = 0 R1 → 1101.
What is 255 in binary?▾
255 in binary is 11111111 (eight 1s). This is significant because 255 is the maximum value of a single byte (8 bits), used in IP addresses and RGB color values.