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Binary to Decimal Calculator – Convert Binary to Decimal & Vice Versa

Binary ⇄ Decimal

The Binary to Decimal Calculator converts binary numbers (base‑2) into decimal (base‑10) and vice versa. Binary is the native language of computers – all data, from text to images, is stored as sequences of 0s and 1s. Understanding how to convert between these systems is essential for computer science, electronics, and programming. This calculator shows each step using place values (powers of 2) or the division‑by‑2 method, making it a perfect learning tool.

Binary Place Values1286432168421Each position = power of 2Example: 1010₂ = 1×8 + 0×4 + 1×2 + 0×1 = 10

Binary to Decimal Formula

Decimal = Σ (binary_digitᵢ × 2⁽ⁿ⁻¹⁻ⁱ⁾)

Where n is the number of digits, and the rightmost digit has exponent 0.

How to Convert Binary to Decimal (Step‑by‑Step)

  1. Write the binary number.
  2. For each digit, note its place value (powers of 2 from right, starting at 2⁰).
  3. Multiply each digit by its place value.
  4. Sum all the products – the result is the decimal number.

How to Convert Decimal to Binary

  1. Repeatedly divide the decimal number by 2.
  2. Record the remainder (0 or 1) after each division.
  3. Continue until the quotient becomes 0.
  4. Read the remainders from bottom to top – that is the binary representation.

Real‑World Applications

  • Computer architecture: Understanding memory addressing, bitwise operations.
  • Networking: IP addresses are often represented in binary.
  • Digital electronics: Logic gates and circuit design use binary.
  • Programming: Bit flags, permissions, and compression algorithms.
Why Binary?

Computers use binary because electronic circuits have two stable states: on (1) and off (0). Binary arithmetic is simple and reliable. The binary system is the foundation of all digital computing, and converting between binary and decimal is a core skill for any computer scientist or engineer.

Common Binary‑to‑Decimal Conversions

BinaryDecimal
11
102
113
1004
1015
1106
1117
10008
10019
101010

Common Mistakes When Converting Binary

  • Forgetting that the rightmost digit is 2⁰: Place values increase leftwards, not rightwards.
  • Using the wrong base: Binary only uses 0 and 1. Any other digit makes the number invalid.
  • Ignoring leading zeros: 00101 is the same as 101; leading zeros don't change the value.
  • Mixing up order of remainders in decimal‑to‑binary: The first remainder is the least significant bit (rightmost).

Use this binary to decimal calculator for homework, exam prep, or any project that requires number base conversion. The step‑by‑step output builds intuition and ensures you understand the process, not just the answer.

Step‑by‑Step Manual Example

Binary 1011 → Decimal:

Place values: 1×8 + 0×4 + 1×2 + 1×1 = 8 + 0 + 2 + 1 = 11

Decimal 13 → Binary:

13 ÷ 2 = 6 rem 1; 6 ÷ 2 = 3 rem 0; 3 ÷ 2 = 1 rem 1; 1 ÷ 2 = 0 rem 1 → binary 1101

Frequently Asked Questions about Binary & Decimal Conversions

What is binary?
Binary is a base‑2 number system using only digits 0 and 1. Computers use binary because they work with two states: on/off.
How do I convert binary to decimal?
Multiply each binary digit by its place value (powers of 2) and sum the results. Example: 1010₂ = 1×8 + 0×4 + 1×2 + 0×1 = 10.
How do I convert decimal to binary?
Repeatedly divide by 2, record remainders, then read from bottom to top. Example: 13 → remainder sequence 1,0,1,1 → 1101₂.
Can I convert large binary numbers?
Yes, up to 64 bits (JavaScript's safe integer limit). For larger numbers, use BigInt, but this calculator handles typical values.