EveryMemoryTower of Hanoi
Move the whole stack to another peg, one disk at a time, never a larger disk on a smaller one. A free Tower of Hanoi puzzle that quietly trains planning — play it right here.
⚡ Quick answer
The Tower of Hanoi is a puzzle where you move a stack of disks from one peg to another, one at a time, never putting a larger disk on a smaller one. The minimum number of moves is 2ⁿ−1, so three disks take 7 moves, four take 15, and five take 31. It mainly exercises planning and sequencing — thinking a few steps ahead — rather than memory. The honest score is your move count versus the optimal, and versus your own past.
Key takeaways
- Move the whole stack to another peg, one disk at a time, never larger on smaller.
- The fewest possible moves is 2ⁿ−1: 7 for three disks, 15 for four, 31 for five.
- Trains forward planning and sequencing — thinking several steps ahead — not memory.
- Score your moves against the optimal and against your own past, not a ranking.
The Tower of Hanoi is one of the oldest puzzles in the book: a stack of disks on one peg, and the simple-sounding goal of rebuilding it on another — moving one disk at a time and never placing a bigger disk on a smaller one. It looks easy with three disks and gets satisfyingly tangly with five.
Play it above (tap a peg to lift its top disk, then tap where to drop it), then read on for the trick to solving it and what it actually exercises.
How to play
- Pick 3, 4, or 5 disks. Tap a peg to lift its top disk — it highlights.
- Tap another peg to drop the disk there. You can only drop onto an empty peg or a larger disk.
- Move the entire stack to a different peg to win.
- Your move count is shown against the fewest possible (2ⁿ−1); your best per disk count is saved on your device.
It all runs in your browser — no sign-up, nothing sent anywhere.
The trick to solving it
There's a clean recursive idea behind it: to move a stack of n disks to the target peg, first move the top n−1 disks to the spare peg, move the biggest disk to the target, then move those n−1 disks on top. Each size repeats the same plan.
A simple hands-on rule also works: always move the smallest disk every other turn, and always in the same direction (for example, rightward, wrapping around); on the in-between turns, make the only other legal move. Follow that and you'll solve it in the optimal number of moves.
What it trains
Tower of Hanoi is a classic test of planning and problem-solving:
- Forward planning — holding a multi-step plan in mind before you act.
- Sequencing — ordering sub-goals so they don't undo each other.
- Working memory — keeping track of where you are in the plan.
- Patience and error-checking — noticing when a move leads to a dead end.
Like any single puzzle, it mostly makes you better at itself and similar planning tasks — it's an enjoyable workout, not a proven way to raise general intelligence.
The honest way to read your score
Two fair comparisons: your moves versus the optimal (2ⁿ−1), and your own time across attempts. Solving five disks in 31 moves is a perfect game — chasing that is far more meaningful than any made-up ranking.
If you like planning puzzles, sudoku is a different flavour of the same logic muscle, and you can browse more in our memory games guide. For a self-relative check you can repeat, try the memory test online.
⚠ When to talk to a professional
This is a non-medical puzzle game for fun and practice, not a test of intelligence or brain health. Puzzle performance varies with practice and familiarity. If you're worried about a real, persistent change in your thinking or memory, speak with a qualified healthcare professional rather than reading anything into a game score.
