About Connect 4
Connect 4 is the classic four-in-a-row strategy game, and here you can play Connect 4 online free — against a computer opponent with four difficulty levels or against a friend on the same screen. Drop your red discs into the upright grid, block your rival's yellow discs and be the first to line up four in a row.
The rules take ten seconds to learn, but the game rewards real planning. Good players think in threats: spaces that would complete a line of four. Build two threats at once and your opponent can only block one of them.
Our version plays smoothly on phones, tablets and computers. Pick Easy or Medium to practice (with undo), step up to Hard, or take on Expert, a deep-searching engine that punishes mistakes. Wins against Hard or Expert build a streak that counts on the Connect 4 leaderboard.
How to play Connect Four
- 1
Choose your opponent
Select vs CPU and a difficulty, or 2P to play a friend on the same device. In 2-player mode red and yellow take turns, and whoever starts alternates every game.
- 2
Drop a disc
Click or tap any column that isn't full. Your disc falls to the lowest empty space in that column. On a computer you can also press 1–7, or aim with the arrow keys and press Enter.
- 3
Connect four
Line up four of your discs in a straight line — across, up and down, or on either diagonal — to win. The winning line lights up the moment it's made.
- 4
Block your opponent
Every turn, check whether your opponent could complete four on their next move. If they can, drop a disc in that spot first, unless you can win immediately yourself.
- 5
Keep the streak alive
Wins against the Hard and Expert computers add to your win streak. A loss resets it, and so does abandoning a game you have started, so finish every game you begin.
Controls
| Input | Action |
|---|---|
| Click / tap a column | Drop a disc in that column |
| 1 – 7 | Drop a disc straight into column 1 to 7 |
| ← / → then Enter | Aim a disc with the arrow keys and drop it |
| U or Backspace | Undo (Easy, Medium and 2-player games) |
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Connect Four tips and strategy
Own the center column
The middle column is part of more possible fours than any other column. Starting there, and keeping a strong presence in it, gives your discs the most ways to connect.
Look for double threats
The most common way to win is a fork: one move that creates two separate ways to finish four. Your opponent can block only one, so the other wins the game.
Never play directly under an enemy threat
If your opponent needs a particular space to win, don't fill the space right beneath it. That lets them drop their disc on top and complete the line.
Use odd and even rows
Counting rows from the bottom as 1 to 6, the player who moved first benefits most from threats on odd rows (1, 3, 5), and the second player from threats on even rows (2, 4, 6). Late in the game, when the columns fill up, these threats tend to decide who is forced to give way.
Stack threats in one column
Two of your threats directly on top of each other in the same column are almost impossible to stop. When your opponent blocks the lower one, you complete the upper one.
Count before you commit
Before dropping a disc, ask two questions: does this give my opponent a new winning space, and does it fill a space I might need later? A few seconds of checking prevents most losses.
Practice against Medium, then climb
Medium plays sensibly but makes human-like mistakes, so it's ideal for practicing forks. Once you beat it regularly, Hard will test your defense and Expert your patience.
The computer opponents
- Easy plays mostly at random. It sometimes spots a win or a block, but it leaves plenty of openings, which makes it a good fit for kids and new players.
- Medium looks four moves ahead, counting both players' moves. It never misses an immediate win or lets you win in one move, but it sometimes picks a looser move.
- Hard searches eight moves deep (again counting both sides) with a threat-aware evaluation. It rarely blunders, so you need a real plan to beat it.
- Expert thinks harder the longer the game goes. It searches as deep as time allows, often more than 15 moves ahead, and in the endgame it can calculate every remaining move. Beating it takes strong opening play and a well-timed double threat.
The computer does its thinking in the background, so the board stays smooth even while Expert is working.
A short history of Connect Four
Four-in-a-row games on a vertical grid were sold as Connect Four by Milton Bradley starting in 1974, and the game quickly became a family favorite. It's also known as Four in a Row, Four Up and Gravitrips.
In 1988 the game was mathematically solved independently by James Dow Allen and Victor Allis. With perfect play, the player who moves first can always win by starting in the center column. Starting in either column next to the center leads to a draw, and starting in any other column loses. Perfect play is very hard for a human to keep up, though, which is why the game is still fun decades later. The standard 7×6 board allows roughly 4.5 trillion different positions.
Win streaks and the leaderboard
Games against the Hard and Expert computers are ranked. Every win adds one to your streak and posts it to the Connect 4 leaderboard, where the longest streaks are listed. A loss resets the streak to zero, and a draw leaves it unchanged. Undo is disabled in ranked games, and an unfinished game is saved if you leave the page, so refreshing can't erase a losing position.
Want more head-to-head strategy? Try Checkers, Tic Tac Toe or the tactics in Chess Puzzles, or browse all our board games.
Frequently asked questions
Is Connect 4 a solved game?
Yes. In 1988 James Dow Allen and Victor Allis each proved that the first player can always win with perfect play by starting in the middle column. In practice perfect play is extremely difficult, so games between people remain wide open.
What is the best first move in Connect 4?
The center column. It takes part in the most possible lines of four, and it's the only opening that guarantees a win with perfect play. The two columns beside it are the next-best choices.
Can I play Connect 4 with a friend?
Yes. Choose 2P at the top of the game to play pass-and-play on one phone, tablet or computer. Red and yellow alternate who goes first, and the score is tracked for your session.
How hard is the Expert computer?
Expert uses a deep game-tree search and often looks more than 15 moves ahead. Late in the game it can see all the way to the end. Most players will lose to it at first, but it can be beaten, especially when you move first and take the center.
Do diagonal lines count in Connect 4?
Yes. Four discs in a row count horizontally, vertically or along either diagonal. Diagonal wins are easy to overlook, so check them for both players every turn.
What happens if the board fills up?
If all 42 spaces are filled and nobody has four in a row, the game is a draw. In ranked games a draw doesn't break your win streak.
Is this Connect 4 game free?
Yes. It's completely free and runs in your browser with no download or account. Your streak, stats and any unfinished game are saved on your device.