Sudoku Online: Free Puzzles from Kids 4 × 4 to Hard

Play sudoku online, free, with no download or sign-up. Choose Easy, Medium or Hard 9 × 9 sudoku, or a Kids 4 × 4 sudoku with pictures instead of numbers (from about age 4) and a Kids 6 × 6 sudoku for ages 6 and up. Fill every row, column and box with each number once. Every puzzle has exactly one solution and can be solved by logic alone, with no guessing; Hard puzzles need more than the simplest steps. Pencil in notes, check your grid, take a hint or undo as often as you like, and press “Larger print” for big numbers. There are 10,000 puzzles at each level, a new one with every “New game”, plus Today’s puzzle, the same for everyone.

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How to play

Pick a level (or play today’s puzzle). Fill every empty square so that each row, each column and each box (the squares inside the thicker lines) has every number once: 1 to 4 in a 4 × 4 grid, 1 to 6 in 6 × 6, 1 to 9 in 9 × 9.
Tap or click a square, then tap a number button below the grid (or type the number). The numbers already printed in the grid can’t be changed.
Not sure yet? Turn on “Notes” and tap numbers to pencil small possibilities into a square. Notes in the same row, column and box clear themselves when you place a number.
The squares in the chosen square’s row, column and box are shaded, and every square with the same number is highlighted, to help you look.
“Check” outlines any square that is wrong. “Hint” fills in one square for you (a wrong one first). “Undo” takes back your last move. Fill the whole grid correctly to win.
Keyboard: arrow keys move, a number key fills the square, N switches notes on or off, Delete or Backspace clears a square, H gives a hint, U undoes.

Who it’s for: Kids from about age 4 (4 × 4 with pictures), older kids, grown-ups and seniors (press “Larger print”). Sound is off unless you turn it on, there is no time limit, and “Pause” stops the clock.

Sudoku online tips and strategy

Look for singles: a square where only one number can go because the other eight are already in its row, column or box.
Cross-hatch: pick a number, say 5, and look at each box in turn. Where can a 5 go once you rule out the rows and columns that already have one?
Use Notes on Medium and Hard. Pencil in the options for a square, and they are cleared from its row, column and box as you place numbers.
Easy puzzles need only singles; Hard needs more, like two squares in a row that share the same two options (a pair).
The 4 × 4 picture sudoku is the best start for children: each row, column and 2 × 2 box has each picture once.

Prefer pencil and paper?

Print sudoku for kids (picture sudoku from age 4, then 6 × 6 and 9 × 9), large print sudoku for seniors, or today’s daily sudoku as a PDF with answers. More logic puzzles: nonograms online.

Questions

Which level should I choose?

Kids 4 × 4 suits children from about age 4, especially with pictures on, and is a good warm-up for anyone new to sudoku. Kids 6 × 6 is for ages 6 to 8. Easy 9 × 9 has lots of numbers filled in and only needs looking for the one place a number can go; Medium has fewer; Hard needs a little more thinking, such as spotting where a number must go inside one box. None of them need guessing.

Does every sudoku have one answer?

Yes. Every puzzle has been checked by a computer to have exactly one solution, and to be solvable by logic alone at its level. If you get stuck, use Notes to write the possibilities in, or ask for a Hint.

Is it good for seniors?

Yes. Press “Larger print” for big numbers and buttons (it is remembered on every game), there is no clock to beat (the time is only for your own record), Pause stops it, and Check and Hint are always there. You can type numbers on a keyboard or tap the big number buttons. Sound is off unless you turn it on.

How many puzzles are there?

10,000 at each of the five levels: type a puzzle number to go back to one, or press “New game” for another. “Today’s puzzle” is the same for everyone each day, so a family, a class or a care-home group can all do the same one. For one easy, medium and hard sudoku a day that also prints, see the daily sudoku.

Can I print a sudoku?

Yes: sudoku for kids (picture 4 × 4, 6 × 6 and 9 × 9) and large print sudoku print on one page with the answer on the next, and the daily sudoku prints as a PDF with its answer key.

Is it safe for children?

Yes. There is no chat, no account, no in-game purchases and no links to other sites. Adverts on the page are non-personalised and sit below the game, away from where children tap.

Is it free? Do I need to sign up or download anything?

It is free and plays in your web browser on a computer, tablet or phone. There is nothing to download and no account. Your stats are kept in this browser only. A few adverts on the page, kept well away from the game, pay for the site.

If you like Sudoku online, try

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