Sudoku
Fill one board so every row, column and box holds each symbol once. Numbers, shapes or colors.
Example
Example
An example to explore. No score or practice round is recorded.
A small board. The boxes are two across and two down. Work out each square from its row, its column and its box.
Each square holds a number, from 1 up to the width of the board.
1 puzzle · No time limit · Your place is kept in this browser
One answer, reached by reasoning alone. No guessing.
Continue your unfinished round
Your answers are saved in this tab. Continue from where you left off.
Continuing uses no additional practice start.
Discard the unfinished round?
Your answers from this round will be discarded. You can choose your settings before starting a new round.
Starting the new round uses one practice start.
- Squares filled
- 0 / 81
- Time
- 0:00
Hints used: 0
Marked as you go: 0
Fill every row, column and box
Choose a board, then press Start. Tap a square, then tap a symbol to fill it.
On a keyboard, the arrow keys move and the number keys fill. Backspace erases. N turns notes on and off. Escape ends the puzzle.
The 9 by 9 board is easier to read on a tablet than on a phone.
On, a wrong entry is marked as soon as you make it. Off, nothing is marked until you press Check.
- Active time
- Hints used
- 0
- Marked as you go
- 0
- Squares filled
Round details
This is one puzzle, timed. The time is yours to beat. It says nothing about your intelligence.
Explore the method
Learn the two steps that start most sudoku puzzles. Scanning by symbol beats scanning by square.
On by default unless you turn it off. Saved choices are kept. Shares starts, completions, replays and error categories. For ChatGPT visits, starts and completions may include the first QuickenBrain page and country. No answers, drawings or names.
How this data is usedHelp
Sudoku is one board. Fill every square so that each row, each column and each box holds every symbol once.
There are three sizes. The 4 by 4 board has boxes two across and two down. The 6 by 6 board has boxes three across and two down. That makes three rows of two boxes. The 9 by 9 board has boxes three across and three down.
You can play with numbers, with shapes or with colors. It is the same puzzle in all three. Shapes and colors are there for anyone who would rather not use numbers. Every color carries a small shape as well. You never have to tell two colors apart.
A level is a board size and the hardest step the puzzle needs. The easy levels ask you to look at one square. Rule out what its row, its column and its box already hold. The next levels ask you to find a symbol with one place left. Look along a row, a column or a box. The hardest level needs a pair step. There are three kinds. The Puzzle menu describes them. A hint names the one it used. No puzzle here needs guessing. Every puzzle has one answer.
The clock starts when the board appears and stops when the board is full and right.
Hint first points to useful cells or clues. Press Explain and apply to see the reason and apply that one step. An applied hint counts once.
Check as you go marks a wrong entry the moment you make it. Those are the entries counted on the results. Entries already on the board are marked but not counted. With it off, nothing is marked until you press Check.
Your place is kept in this browser while you work. New puzzle clears it. Only a solved puzzle is saved to your statistics.
The statistics page compares your times at the same board. Only puzzles solved with no hints are counted, so the times mean the same thing.
About this practice
Fill every row, every column and every box with each symbol once. Play with numbers, shapes or colors.
Learn a method
Find the only placeReport a problem
On by default unless you turn it off. Saved choices are kept. Shares starts, completions, replays and error categories. For ChatGPT visits, starts and completions may include the first QuickenBrain page and country. No answers, drawings or names.
How this data is used