Medium Sudoku

Your medium Sudoku stats

Finished medium puzzles are recorded in your browser (your last 25 games), so you can watch yourself improve. Nothing leaves your device.

See every level, your streaks and your recent games on the Sudoku stats page.

How difficult is Medium Sudoku?

Medium Sudoku is the step between beginner and serious solving. Each puzzle starts with about 35 of the 81 cells filled in, leaving around 46 empty cells. That is ten fewer clues than an easy puzzle, so scanning alone will usually stall partway through and you will need a second tool.

The jump from easy is real but manageable. You still do not need advanced patterns: the usual answer is to look for hidden singles and to start using pencil notes in the tightest rows, columns and boxes.

Times vary a lot from player to player; treat them as a rough guide, not a target. For a deeper comparison, see Sudoku strategies for every level.

How Medium Sudoku works

The rules are unchanged: each row, column and 3×3 box holds the digits 1 to 9 exactly once (see the Sudoku rules). What changes on medium is how you find the next number:

1. Scan first. Place every number that scanning and naked singles give you, just like on easy.
2. Switch to hidden singles. Look at a row, column or box and ask where a particular digit can still go. If it fits in only one cell, it belongs there even if that cell has other candidates.
3. Add notes where it is tight. When both of those stop working, pencil in the candidates for the busiest area and look for cells with a single candidate left.
4. Re-scan after each placement. Every new number can unlock a naked or hidden single next to it.

Every puzzle has exactly one solution, so guessing is never required.

Tips for solving Medium Sudoku

• Learn hidden singles. They are the main new skill at this level. Check each box for a digit that has only one possible home.
• Use notes selectively. Do not fill every cell. Write candidates only in the box, row or column that is nearly full, where the list stays short.
• Keep notes honest. When you place a number, erase it from the notes in its row, column and box straight away.
• Scan in a fixed order. Go through 1 to 9 in turn so you do not keep rechecking the same digit.
• Start with digits that appear often. A digit that already appears seven or eight times is the quickest to complete.
• Switch areas when stuck. A placement in another part of the grid often unblocks the stalled region.

Read Sudoku techniques explained for hidden singles with examples, and Sudoku strategies for how to decide when to use notes.

Common mistakes to avoid

• Writing notes everywhere. Full notes on a grid with 46 empty cells are slow and error-prone. Use them only where they pay off.
• Letting notes go stale. An old candidate you forgot to erase will mislead you into a wrong number.
• Only hunting for naked singles. Cells with several candidates can still be solved by asking which digit fits only there.
• Guessing between two options. A 50/50 guess on a medium puzzle usually means a hidden single or pair has been overlooked.
• Ignoring the box. Check the 3×3 box as carefully as the row and column.

Hints, notes, timer and other tools

Everything in the game above is free and available at every level:

• Hints: three per game. A hint fills in one correct cell. Press H as a shortcut.
• Notes: turn on pencil notes to mark possible digits in a cell. Medium is where notes start to matter, so practice using them in one tight area at a time. Press N to toggle.
• Undo and erase: take back any move as many times as you like with Undo or Ctrl+Z.
• Timer: your solving time is shown above the board. Select it or press Pause to stop the clock while you take a break.
• Mistake counting: switch it on to end the game after three wrong numbers, a good challenge once you are comfortable.
• New puzzle: press New Puzzle for a fresh medium grid whenever you like.
• Autosave: close the tab mid-game and your puzzle is waiting when you come back.
• Keyboard: arrow keys to move, 1–9 to enter a number, Backspace to erase.

Prefer to check a puzzle from a newspaper or book? The Sudoku solver solves any grid you type in.

Print medium Sudoku

Like solving with a pencil? Generate a free sheet of medium Sudoku puzzles on our printable Sudoku page, choose the layout and paper size, and print or save it as a PDF.

Ready for another level?

Once you can finish medium puzzles without hints in roughly fifteen minutes, try the neighboring levels:

Want a fresh puzzle everyone plays? Try the Daily Sudoku, or switch to a different grid size with Sudoku variants such as 4×4 and 6×6.