What Is the International Date Line?

The International Date Line (IDL) is an imaginary line on the Earth's surface that separates one day from the next.

Quick Answer

The International Date Line is an imaginary line in the middle of the Pacific Ocean. When you cross it going west, you add a day, and when you cross it going east, you subtract a day. It's where a new day officially begins on Earth.

The International Date Line is located at about 180° longitude. When you cross the IDL from west to east, you subtract a day, and when you cross it from east to west, you add a day. It intentionally zigzags to avoid crossing through any countries.