About Zen Fifteen
Zen Fifteen is the classic 15 sliding puzzle — arrange tiles numbered 1 to 15 in order by sliding them one at a time into the empty space. The fewer moves you use, the higher your score and the higher your rank on the city leaderboard. Simple to understand, endlessly challenging to master. The world record is 43 moves. The average player takes over 150.
Frequently Asked Questions
What is the 15 puzzle?
The 15 puzzle is a classic sliding tile puzzle invented in the 1870s. A 4x4 grid holds 15 numbered tiles and one empty space. You slide tiles one at a time to arrange them in numerical order from 1 to 15.
How is the score calculated?
Score = 10000 minus (moves × 40) minus (seconds × 5). Fewer moves and faster time both improve your score. Moves count more than time.
Is every puzzle solvable?
Yes. Zen Fifteen only generates solvable configurations. Exactly half of all random arrangements are unsolvable — we check and regenerate if needed.
Is it free and unblocked?
Yes. Completely free, no download, works on any browser including school Chromebooks and mobile.
What is a good score?
Under 60 moves is excellent. Under 45 moves is expert level. The mathematical minimum for any puzzle is around 43 moves.