Best way to start
Look for crowded rows, columns, and boxes. A nearly finished area gives fewer legal options, so it is usually the fastest place to find a certain number.
Sudoku Duck
Free Sudoku Online
Sudoku Duck is a free online Sudoku website where you can play easy, medium, hard, and expert puzzles, use notes and hints, print Sudoku sheets, and solve puzzles step by step.
Choose a square, then tap a number.
At a glance
What can you do on Sudoku Duck?
| Difficulty | Best for | Solving style | Average time | Recommended techniques |
|---|---|---|---|---|
| Easy | New players and warmups | Mostly direct scanning | 5 to 10 minutes | Rows, columns, boxes, simple singles |
| Medium | Daily practice | Scanning plus notes | 10 to 20 minutes | Candidates, single candidates, hidden singles |
| Hard | Patient solvers | Careful candidate tracking | 20 to 40 minutes | Locked candidates, pairs, repeated review |
| Expert | Advanced practice | Sparse clues and deeper logic | 30 minutes or more | Pairs, box-line reduction, X-Wing basics |
How it works
How Sudoku works
A standard Sudoku puzzle has 81 squares arranged in a 9x9 grid. The goal is to fill every empty square with a number from 1 to 9 so each row, each column, and each 3x3 box contains every number once. The starting numbers are fixed clues, and every answer must agree with all three areas at the same time.
When to use notes
Use notes after the obvious placements slow down. Write only real candidates that survive row, column, and box checks.
Avoid guessing
If two numbers both seem possible, keep them as notes and scan elsewhere. A later placement may remove one of them.
| Need | Best page | Why it helps |
|---|---|---|
| Quick puzzle with hints | Free Sudoku Online | Use the board, timer, notes, hints, and checking in one place. |
| Paper practice | Printable Sudoku | Print two or four puzzles with solution grids below. |
| Check a copied puzzle | Sudoku Solver | Validate rows, columns, and boxes before solving the grid. |
| Learn the rules | How to Play Sudoku | Follow beginner steps and examples before playing harder levels. |
Welcome
What is Sudoku Duck?
Sudoku Duck is a free puzzle website made for people who want a quiet, clear place to play Sudoku. The board is built for phones, tablets, laptops, and desktop screens, and the controls stay simple: select a square, choose a number, switch on notes when you need pencil marks, and use a hint when you are stuck. There is no sign-up wall, no download prompt, and no distracting topic that pulls the site away from puzzles.
The site is meant to feel useful from the first visit. You can play online, print a clean puzzle sheet, solve a puzzle you found somewhere else, or read the rules before starting. Beginners can use the Easy Sudoku page and the how-to guide. Regular players can move through Medium, Hard, and Expert puzzles as their scanning and note skills improve. Teachers, parents, and commuters can use the printable page for paper practice.
Sudoku itself is simple to describe but satisfying to learn. Fill every row, column, and 3x3 box with the numbers 1 through 9. A good puzzle does not need guessing. Each solved number should follow from the clues already on the board. Sudoku Duck keeps that spirit in mind by pairing playable grids with plain explanations, beginner tips, and printable practice that works away from the screen.
Difficulty
Choose your Sudoku difficulty
Easy Sudoku
Best for new players, warmups, and relaxed practice. Easy puzzles have more starting clues and usually solve with scanning and single candidates.
Play EasyMedium Sudoku
A balanced level for daily play. Medium puzzles ask you to use notes more often while still staying friendly.
Play MediumHard Sudoku
A better fit when you are ready to slow down, compare boxes, and watch for hidden singles.
Play HardExpert Sudoku
Built for patient solving. Expert puzzles have fewer clues and reward careful pencil marks from the start.
Play ExpertIf you are unsure where to begin, play one Easy puzzle without notes and one Medium puzzle with notes. That pair will show whether you want a quick solve or a deeper challenge. The New puzzle button gives you a fresh board, and the difficulty selector lets you change level without leaving the game.
Daily play
Daily Sudoku challenge
A short daily puzzle routine is one of the easiest ways to get better. The Daily Sudoku page gives you a fresh-feeling challenge you can use as a morning warmup, a lunch break reset, or a calm evening habit. Try solving the first half of the puzzle without notes, then switch on notes only when the board stops giving you obvious placements.
Daily play also helps you notice patterns. You start to see which boxes are crowded, which rows have only a few missing numbers, and which columns are likely to unlock the next step. Small steady practice matters more than rushing through a hard board once in a while.
Paper puzzles
Printable Sudoku puzzles
Sometimes paper is the better tool. Printable Sudoku gives you space to write pencil marks, circle important clues, and solve away from notifications. Sudoku Duck includes clean printable sheets with two or four puzzles per page and solution grids below the puzzles. The print stylesheet removes the header, footer, buttons, and screen controls so the page stays tidy on paper.
Printed puzzles work well for classrooms, family trips, waiting rooms, and puzzle folders. Choose a difficulty, pick the number of puzzles per sheet, and print. If you want answers for checking later, keep the solution section on the same printout.
Tool
Sudoku solver tool
The Sudoku Solver is there for learning and checking, not for taking the fun out of every puzzle. Enter the givens from a puzzle, run validation, and the tool will show a solved grid when the puzzle is valid and solvable. If the puzzle has a conflict, such as two 7s in the same row, the solver explains that the starting grid needs correction.
A solver is most useful after you have tried a puzzle by hand. Compare the solved grid with your notes, look for the square that blocked you, and ask which rule would have found it. Used that way, the solver becomes a practice partner instead of a shortcut.
Basics
How to play Sudoku
Start by reading the grid in three directions: across rows, down columns, and inside each 3x3 box. A number is allowed only when it does not already appear in those three places. Look for crowded areas first. If a row already has seven numbers, the last two numbers are easier to test. If a box has only one empty square, that square must take the missing number.
When the easy placements run out, turn on notes. Notes are small pencil marks that track the possible numbers for a square. They keep your thinking visible and reduce repeated work. Good notes are not decoration; they are a map of what the puzzle still allows.
Practice
Beginner tips
- Scan one number at a time. Ask where all the 1s can go, then where all the 2s can go, and so on.
- Use notes when a square has two or three real options. Avoid filling every blank with every number.
- Check rows, columns, and boxes before placing a number. One quick check prevents most mistakes.
- Pause when you feel tempted to guess. A fair Sudoku puzzle has a logical next step.
Sudoku rewards a calm pace. The board often opens after one careful placement, so take a breath, look for the most crowded area, and let the puzzle give you the next clue.
Questions
FAQ
What is Sudoku Duck?
Sudoku Duck is a free Sudoku website where you can play online puzzles, print puzzle sheets, use a solver, and learn the rules at your own pace. It is built around a clear 9x9 board, simple controls, and beginner-friendly guides. Start with Free Sudoku Online, then use the guides when you want more confidence.
Is Sudoku Duck free to use?
Yes, Sudoku Duck is free to use for online play, printable puzzles, the Sudoku Solver, and the learning pages. You do not need an account to start a puzzle. You can choose a difficulty, use notes and hints, print sheets, or check a copied puzzle without paying or installing anything.
How do I play Sudoku online?
To play Sudoku online, choose an empty square and enter a number from 1 to 9 that fits its row, column, and 3x3 box. Original clues stay locked, and your job is to fill the remaining squares logically. On Sudoku Duck, you can use notes for candidates, check mistakes, request a hint, or start a new puzzle.
Which Sudoku difficulty should I choose first?
Choose Easy Sudoku first if you are new or returning after a break. Easy puzzles usually reward scanning rows, columns, and boxes before heavy note-taking is needed. Move to Medium when Easy puzzles feel steady, and try Hard or Expert only when you are comfortable tracking candidates and reviewing notes carefully.
Does Sudoku require math?
No, Sudoku does not require math or arithmetic. The numbers are symbols used to organize the grid. You never add, subtract, multiply, or divide them. A correct move comes from logic: the same number cannot repeat in a row, column, or 3x3 box.
What are pencil marks or notes in Sudoku?
Pencil marks, also called notes, are small candidate numbers that show which values may still fit in an empty square. They help when a square has two or three realistic options. Good notes should be checked against the row, column, and 3x3 box, then updated whenever a new answer removes a candidate.
Can I print Sudoku puzzles from Sudoku Duck?
Yes, you can print Sudoku puzzles from the Printable Sudoku page. Choose a difficulty, pick a sheet size, and use your browser print preview to print clean puzzle grids. Printed puzzles are useful for paper notes, classrooms, travel, or solving without a screen.
Can I use the Sudoku Solver if I get stuck?
Yes, you can use the Sudoku Solver when you are stuck or want to check a puzzle you copied from paper. Enter the given numbers, leave blanks empty, and let the tool validate the grid. For learning, compare the solved grid with your notes instead of treating the answer as only a shortcut.
Does every Sudoku puzzle have one solution?
A proper classic Sudoku puzzle should have one solution, because the grid is meant to be solved by logic rather than choice. If a puzzle has multiple solutions, it may not have enough clues to force a single answer. If it has no solution, a clue or entered number may be wrong.
Is Daily Sudoku different from a regular puzzle?
Daily Sudoku is a regular Sudoku puzzle used as a simple daily practice routine. The rules do not change: every row, column, and 3x3 box still needs the digits 1 through 9 once. The difference is the habit. A daily puzzle gives you one focused grid to solve and review.
Can I play Sudoku Duck on a phone or tablet?
Yes, Sudoku Duck is designed for phones, tablets, laptops, and desktop screens. Tap a square, use the number pad, and switch notes on when you need pencil marks. The same rules and tools work across screen sizes, though careful note-taking may feel easier on a larger display.
How can beginners get better at Sudoku?
Beginners get better by solving slowly, checking all three areas before each placement, and reviewing stuck moments after the puzzle. Start with Easy puzzles, learn the rules in How to Play Sudoku, and use Sudoku Tips when you are ready for candidates, hidden singles, and cleaner notes.
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