What is SudokuSwap?

SudokuSwap turns sudoku inside out. Instead of an empty grid waiting to be filled, every puzzle starts with a completely filled board whose tiles have been scrambled. Your job is to swap pairs of tiles until every digit sits in its correct spot. The solution is always a valid sudoku: each row, column, and 3×3 box contains the digits 1 through 9 exactly once.

Three new puzzles are published every day — one easy, one medium, and one hard — and every puzzle can be solved in a known minimum number of swaps. Finish at that minimum and you earn a perfect five-star rating. Each extra swap beyond the minimum costs you stars, so the real challenge isn't just solving the board — it's solving it efficiently.

How to play

Tap one tile, then tap another to swap them. The colors tell you everything you need to know: a green tile is already in its correct position and can't be moved, a yellow tile belongs somewhere nearby — in the same row, column, or 3×3 box — and a plain tile belongs somewhere further away. When a swap lands both tiles on green at once, you've made a perfect swap, and the board celebrates with you.

If you're stuck, the hint button will point out a helpful swap, at the cost of two extra moves toward your rating. You can play today's three puzzles or browse the calendar to replay any daily puzzle from the archive.

Tips and strategy

Start by scanning for pairs of tiles that are simply holding each other's places — swapping them fixes two cells in a single move, which is the foundation of an efficient solve. When no perfect swaps remain, look for three tiles that form a cycle and plan the two swaps that resolve it rather than moving tiles one at a time.

Yellow tiles are your compass. A yellow tile in a row tells you its digit stays in that row, so check the row's other open cells before looking anywhere else. Solving the corners and edges of a 3×3 box first often forces the remaining tiles into place. And before any swap, ask whether it brings at least one tile home — swaps that green neither tile are usually wasted moves, and the game privately tracks your swap accuracy so you can watch it improve.

Frequently asked questions

Is SudokuSwap free?

Yes. Every puzzle — today's three dailies and the entire archive — is free to play. The site is supported by advertising.

Do I need an account?

No. You can play forever without signing in; your progress is saved in your browser. Creating a free account adds cross-device sync of your stats and streaks, plus a spot on the global leaderboards for fastest solves and longest daily streaks.

How are the star ratings calculated?

Every board has a known minimum number of swaps. Match it for five stars; each small band of extra swaps beyond the minimum drops the rating by one star. Using a hint adds two swaps to your count.

When do new puzzles arrive?

At midnight in your local time zone, every day — one puzzle each in easy, medium, and hard.

What happens if I close the page mid-puzzle?

Your in-progress board is saved automatically and resumes exactly where you left off, including your swap count and remaining hints.