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Binary Calculator – Add, Subtract, Multiply Base 2

Quick answer

Do arithmetic in base 2 with carries shown: 1011+110=10001 (11+6=17), 101×11=1111 (5×3=15).

  • Two’s complement notes included.

Figures are estimates from this calculator’s standard formula — adjust the inputs in the tool below for your exact number.

How the Binary Calculator Works

1+1 = 10 (carry 1) | subtraction via borrows | multiplication as shifted adds

Binary arithmetic follows the same column rules as decimal, except carrying happens at 2 instead of 10. Adding 1011 (eleven) and 110 (six): right column 1+0 = 1; next 1+1 = 10, write 0 carry 1; then 0+1+1 = 10, write 0 carry 1; then 1+1 = 10, producing 10001 — seventeen, verified in decimal. Subtraction borrows similarly, or converts to two’s complement: to compute 1011 − 110, negate 110 in four bits (invert 0110 → 1001, add 1 → 1010), then 1011 + 1010 = 10101, and dropping the leading carry leaves 101 — five. Multiplication is shifted addition: 101 × 11 = 101 + 1010 = 1111, exactly 5 × 3 = 15. The calculator prints every carry and borrow row, the decimal cross-check, and the two’s-complement trace for negative results.

  1. 1

    Enter two binary numbers

    Only 0s and 1s — the parser rejects other digits

  2. 2

    Choose the operation

    Add, subtract, multiply or divide

  3. 3

    Follow the carries

    Each column’s sum, carry and borrow is displayed

  4. 4

    Cross-check in decimal

    The decimal equivalents confirm the binary result

Use Cases

Computer Science Class

Hand-verify ALU exercises like 1011 + 110 = 10001

Digital Logic Labs

Check adder outputs and two’s complement conversions

Bitmask Crafting

Combine flags 1100 OR 0011 = 1111 for permission sets

Tips

  • 1

    In binary, 1+1 = 10 — carry the one, write the zero

  • 2

    Negative numbers use two’s complement: invert bits and add 1

  • 3

    Multiplying by 2 just appends a 0: 101 → 1010

Common Mistakes

  • Writing 1+1 = 2 in a column — binary has no digit 2

  • Forgetting the final carry, reading 10001 as 0001

  • Treating two’s complement as simple inversion without the +1

  • Multiplying 101×11 as 1111×... mixing up operand order in long multiplication

FAQs

What is 1011 + 110 in binary?

10001. In decimal: 11 + 6 = 17, and 17 = 10001₂.

What is 101 × 11?

1111₂ = 15: shifted adds give 101 + 1010 = 1111, matching 5 × 3.

How does binary subtraction with borrows work?

0−1 borrows from the next column, becoming 10−1 = 1. For 1000 − 1 the borrow cascades to 111.

How do I represent −3 in two’s complement?

3 = 0011; invert to 1100, add 1 → 1101. Check: 0011 + 1101 = 10000, drop the overflow and you get 0000.

Why does appending a 0 double the value?

It shifts digits up one power of 2, like appending 0 in decimal multiplies by 10: 101 (5) → 1010 (10).