Sudoku — Free online & daily sudoku

Sudoku guide

What is this game?

Playfulo Sudoku is free online sudoku in the browser. No sign-up — fill a 9×9 grid with digits 1–9 so every row, column, and 3×3 box contains each digit once.

Daily sudoku is one shared puzzle per day (Korea time) — no login required. Streak and best time stay in this browser. Free play offers easy, medium, and hard with notes, undo, and single-cell hints.

The board and number pad scale for desktop, tablet, and phone. Conflicting digits highlight in red.

How to play

Fill empty cells so each row, each column, and each 3×3 box contains 1–9 exactly once. Pre-filled clue cells cannot be changed.

Never repeat a digit in the same row, column, or box. Conflicts appear in red.
Notes mode lets you mark candidate digits in empty cells. Placing a final digit clears that cell’s notes and removes the same digit from notes in its row, column, and box.
A hint fills one correct cell. Undo reverts your latest entry.
When every cell is filled with no conflicts, you clear the puzzle. Time and move count are shown.

Controls

Tap an empty cell, then enter 1–9 with the number pad. On a keyboard, use digits, arrows, and Delete.
Turn on Notes to mark candidate digits in a cell. Erase clears the cell.
Use Hint to fill one correct cell, and Undo to reverse your last entry.

Strategy tips

Lock a cell when only one candidate remains, and scan rows, columns, and boxes for digits that fit only one place.
When a digit has only two or three possible cells in a box, mark them with notes to avoid mistakes.
If a conflict turns red, revisit that digit first, and save hints for when you are truly stuck.

Difficulty differences

Easy, medium, and hard are not AI settings — they differ by how many clue cells are pre-filled. Easy has more clues for beginners; medium adds blanks; hard is sparse. Daily sudoku uses medium-style clue density as one shared puzzle per day. Every puzzle is a standard unique-solution sudoku.

Common beginner mistakes

Guessing many cells makes recovery hard — narrow candidates first.
Check the whole row, column, and box — not just one cell.
Daily sudoku is fixed per day — use notes/hints when stuck.

FAQ

Can I play sudoku online for free?

Yes. Play free sudoku on Playfulo with no sign-up. Try the daily challenge or easy, medium, and hard free play, with notes, undo, and hints on desktop, tablet, or mobile.

What are the sudoku rules?

Fill a 9×9 grid so each row, column, and 3×3 box contains digits 1–9 once. Pre-filled numbers are clues and cannot be edited.

What is daily sudoku?

Daily sudoku is one shared puzzle per calendar day (Korea time). No login — everyone gets the same board. Clear time and streak are saved in this browser, and you can share a result text with friends.

What is the difference between easy, medium, and hard sudoku?

Harder levels start with fewer pre-filled clues and more empty cells. Easy is for beginners, medium for regular play, and hard for focused sessions. The daily puzzle uses medium-style clue density.

Can I play sudoku on mobile?

Yes. The board and number pad scale on phones and tablets. Tap a cell, then a digit — or use a keyboard with 1–9, arrows, and N for notes when available.