Binary Numbers Explained: How Computers Think in 1s and 0s
Every photo, video, message, and program on your computer is made of just two digits. Here is how.
Binary is base-2: only two digits, 0 and 1. Decimal (what humans use) is base-10. In binary, each position represents a power of 2 instead of a power of 10. The binary number 1101 = 1×8 + 1×4 + 0×2 + 1×1 = 13 in decimal.
Why Computers Use Binary
Transistors — the building blocks of processors — have two states: on (1) and off (0). Building reliable hardware with two states is vastly simpler than building hardware that distinguishes between ten voltage levels. Modern processors contain billions of transistors, each switching between on and off billions of times per second.
How Text Becomes Binary
ASCII assigns each character a number: A=65, B=66, a=97, space=32. The number is stored in binary: A = 01000001. The word "Hi" = 01001000 01101001 — sixteen 1s and 0s. A single emoji can require 32 bits (four bytes) of binary data.