Drop your discs — get four in a row to win!
Connect Four is a classic two-player strategy game where you take turns dropping colored discs into a 7-column, 6-row vertical grid. The first player to form a line of four consecutive discs — horizontally, vertically, or diagonally — wins the game. Our free online version lets you play against an AI with three difficulty levels.
Click (or tap on mobile) any column to drop a red disc. Discs fall to the lowest available row. The yellow AI responds automatically. Choose Easy for relaxed play, Medium for a real challenge, or Hard for a tough minimax AI with alpha-beta pruning. Your wins, losses, draws, and win streak are saved between sessions.
Control the center column — pieces there offer access to the most winning combinations. Create multiple simultaneous threats so your opponent cannot block everything at once. Avoid placing a disc directly below an open spot that would give your opponent a winning move on their next turn.
Yes! Connect Four is a mathematically solved game. The first player can always force a win with perfect play by starting in the center column (column 4). This was proven independently by James Dow Allen and Victor Allis in 1988. Our Hard AI approximates this level of play using minimax search with alpha-beta pruning.
There are approximately 4.5 trillion possible game positions (4,531,985,219,092 to be precise). The full game tree contains about 69 billion terminal positions. Despite this complexity, a complete solution exists, making Connect Four one of the most studied solved games in combinatorial game theory.
Last updated: March 2026