Best Free Sudoku Puzzle, Generator and Solver

 
Introduction

Sudoku is a simple logic puzzle and number placement game, easy to learn, great for zoning your logic thinking while you play the game.

There is only one rule to completing a sudoku: each 3x3 box, each row and each column, must contain each of the digits from 1 to 9 without repetition (there are nine cells in every row, column and box). The puzzle begins with some cells already numbered. Your task is to fill in all the rest.

While the rule of Sudoku puzzle is pretty simple, but it can be quite a challenging puzzle to solve. Never give up too easily though, the good news is there are free and good programs to help you solve it. They help scan and keep track of possible digits for blank cells, provide filters and color markers to make solving even tricky puzzles much easier, faster and more interesting.

What's more? There are numerous hints and strategies to help play the game and solve the puzzle, such as the ones here and here. Or watch a series of video clips here.

 
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Discussion
Sudoku for Cross-Platform

HoDoKuHoDoKu is an open source program and runs on Windows, Linux or Mac. It allows you to generate sudoku puzzles in five different and configurable difficulty levels. It also includes a solver and an analyzer to help you solve the puzzles.

While playing the game, you can select to view a summary of solving techniques and the solution paths. When you click on a solution path, it highlights the steps on the corresponding grid to help you analyze the game. You can also opt for a practising mode, tick one or more techniques to be included in a new puzzle. All these features make HoDoKu not only a game to play but also a nice tool for learning and honing your skills in the game as well.

Other useful features include redo/undo steps, show candidates and invalid values, next vague or concrete hints and more. Puzzles can only be saved in a proprietary hsol format or a png image format for printing out, whereas import and export of games from/to other formats are not available.

 

SudokuBanSudokuBan is cross-platform (runs on Linux and Windows XP) and requires Python, GTK+, PyGTK to be installed.

What I like most is its clean design and intuitive interface—you just need to right click a cell and select the numbers from a small pop-up window. Better still, you can opt to restrict the numbers that are available for a cell.

With the program, you can create a random puzzle in a standard size of 3x3 box, or increase the size up to 6x6 box.

The games can be saved in a standard text format and opened later to continue the game.

While playing the game, you can check if the puzzle is valid or solvable, or let the program find a solution. On the downside, it has no undo/redo and printing functions.

 

SoloIncluded as part of Simon Tatham's Portable Puzzle Collection, Solo by itself is a small portable program in 156 KB and runs on Windows, Mac OS X and Linux. It even has a Java interface for running in your browser online. You can click here and straight away play the game.

Other than the standard 3x3 box with various difficulty levels, it also provides other optional and custom types to suit your needs.

Even with this tiny program, you're not short changed—standard features including load, save and print games, redo or undo moves, right-click a cell to add a 'pencil mark', and solving puzzles are all supported.

 

Sudoku for Windows

SuDoku CrackerWith SuDoku Cracker, you can create a puzzle, play the game, or get a solution to the puzzle easily.

The program generates sudoku puzzles in high quality with a unique solution. It allows you to create a puzzle in any of 7 difficulty levels starting from 'very easy' to 'Super Sudoku'.

Besides playing the game, you can save or open a game in default sdk or text format, or print the puzzle to paper to fill in or share with others. Trying hard and can't solve the puzzle? The program can give a hint, solve the next step or even the whole puzzle instantly for you.

Many other features are included such as redo/undo moves, show or hide candidate values in blank cells, strike out a number, mark a cell, row, column or box in different colors, etc. Free registration of the program is required after installation.

 

Simple SudokuSimple Sudoku creates challenging puzzles with 5 grades, from 'easy' to 'extreme'. It generates each puzzle randomly, so the selection is practically limitless.

The program has a keyboard and mouse friendly design with adjustable window sizes.

Similar to SuDoku Cracker, it helps scan what are possible digits for blank cells each time you enter a number, with a hint or even solution for the next number, covering almost all logical solutions for you. That's one of the helpful tools to help solve the puzzles—removing the drudgery but keeping the fun for the game.

Other features of the program include redo/undo moves, copy and paste puzzles to and from the clipboard, save, load or print completed or partially completed puzzles, etc. To save a game file in a text format, you need to add ".txt" to the file name.

 

Isanaki SudokuIf you need more varieties, Isanaki Sudoku is a good choice. Not only has it had a standard Sudoku mode, it allows you to switch over to a Wordoku mode easily, entering letters instead of numbers.

The program has 6 levels of difficulty, equipped with a generator and a solver using the brute-force technique and solving most of the hard Sudoku boards. It provides optional 9x9 or 16x16 boards which are configurable by users, but certain buttons in the 16x16 board go beyond the window if not maximized.

Other useful features include hints, redo/undo moves, show mistakes, highlight candidates, print multiple boards, saving and opening, import and export, plus a simple sound effect.

After downloading the zip file, extract it and run the executable directly.

 

Pure SudokuPure Sudoku has 4 levels of difficulty in gameplay, over 40 refreshing backgrounds, and contains 20,000 different sudoku puzzles, enough to play everyday for years. It automatically saves your game progress so that you can adjourn and return to the game anytime.

You can play full-screen or windowed, redo/undo moves, display any duplicate numbers entered, or get the solution to the puzzle with one-click.

On the downside, some other features such as hints, checks, or selectively saving or loading of games are only available with the paid version.

 

Total SudokuIt is easy to start Total Sudoku—run the program, point at a blank cell and key in a number between 1 to 9. It comes with an attractive user interface and lets you automatically generate a new puzzle in any of 3 levels of difficulty ('easy', 'medium' or 'hard').

The program helps by coloring a cell green when you enter a digit correctly, or red if you've got it wrong, but it doesn't include a solver for you.

You can save a game in progress, so you can adjourn and come back whenever you want. Or you print the puzzle to paper to fill in.

 

Other than the above, you might want to try out another solver Gwerdy SuDoku Solver which uses logical methods to help find solutions to most puzzles. It retrieves all cell values at a press of the "Solve" button, or just a single cell digit each time you hit the "Hint" button. The default file format is .spf (sudoku puzzle file), but a text file can be loaded too. Alternatively, a "Load from text" option can be used to paste a sudoku puzzle copied to the clipboard.

 

Sudoku for Linux

KSudokuKSudoku has a flexible user interface with configurable toolbars and themes.

With this program, you can choose a game in a standard size of 9x9 cells in numbers, or 16x16 and 25x25 cells in symbols, or in other shapes such as 3D Roxdoku, Samurai, 4x4, XSudoku and Jigsaw.

KSudoku provides a generator and solver, 5 levels of difficulty, allowing for saving and loading of games played. Hints, redo/undo are available but no printing of the game is supported.

The latest version 0.5 is included in the KDE Games Center and can be downloaded from Ubuntu Software Center as well.

 

Play Sudoku online

Other than Solo mentioned in this article, DKM Sudoku Online is well worth trying. It is almost as fully-featured as any of Sudoku download. Click 'Play Now' and go to 'Menu' to create a new puzzle in any of 4 levels. You can enter possible cell values manually in pencil mode, or let it scan for you. Other features such as undo last move, check for errors, hint, solve one or all cell values are included.

Alternatively, try Daily Sudoku [http://www[DOT]veryfreesudoku[DOT]com/dailysudoku.html, link obfuscated for yellow WOT rating] with unlimited puzzles, online solver and hints.

 

To be reviewed:

  • SudoGu, a generator, helper and solver for many Sudoku variants with 79 solving techniques. The program has a German and English user interface but the homepage is currently written in German.
  • Sudoku Explainer, an interactive Sudoku solver written in Java, explains how to solve a sudoku puzzle with a graphical illustration.
 
Related Products and Links

You might want to check out these articles too:

 
Quick Selection Guide

HoDoKu
5
 
Gizmo's Freeware award as the best product in its class!

Runs as a stand-alone program on a user's computer
Five different and configurable difficulty levels, includes solver and analyzer, summary of solving techniques and solution paths, redo/undo steps, show candidates and invalid values, next vague or concrete hints, etc.
Puzzles can only be saved in a proprietary hsol format or a png image format, no import and export of files are supported.
2.2.0
1.9 MB --> .msi installer
Open source freeware
Windows, Linux or Mac

v2.2.0 released 29 July, 2012

SuDoku Cracker
4.5
 
Runs as a stand-alone program on a user's computer
Create puzzles in 7 levels of difficulty with unique solutions, hint, solve next step or whole puzzle, show/hide candidates, open/save/print puzzles, plus other useful features.
Free registration is required to activate the software after installation.
10.08
1.4 MB
Free for private use only
Win 95 to Win 7
SudokuBan
4
 
Runs as a stand-alone program on a user's computer
Cross-platform, clean design with intuitive user interface. Resizable up to 6x6 box, save and open, generator and solver.
Lacking redo/undo and print functions.
1.0
55.6 KB
Open source freeware
Linux and Win XP (Requires Python, GTK+, PyGTK to be installed)
Solo
4
 
Available either as a web service or stand alone program
Standard 3x3 box with various difficulty levels, optional and custom types, load, save and print games, redo or undo moves, add a 'pencil mark', and solving puzzles.
No import and export of files are supported.
r9976
2.87 MB --> Win32.exe
Open source freeware
This product is portable.
Windows, Mac OS X, Linux, or running online in a browser

You can run this application online in a browser by clicking here.

Mac OS X version is now unsupported and no longer being updated. The last revision is still available from the down load site.

Isanaki Sudoku
4
 
Runs as a stand-alone program on a user's computer
Sudoku and Wordoku modes, 6 levels of difficulty, generator and solver, 9x9 and 16x16 boards, highlight candidates, saving and opening, import and export, etc.
Certain buttons in the 16x16 board go beyond the window if not maximized.
2.6b
606 KB
Unrestricted freeware
Windows 2000 to XP

View the release history here

KSudoku
4
 
Runs as a stand-alone program on a user's computer
Configurable toolbars and themes, 5-levels of difficulty, support 9x9 and many other shapes, generator and solver, hints, redo/undo, saving and loading.
No printing of games.
http://ksudoku.sourceforge.net/
0.4 (0.5 from repositories)
309 KB
Open source freeware
Linux

Newer version 0.5 available from Ubuntu Software Center.

Simple Sudoku
4
 
Runs as a stand-alone program on a user's computer
5 grades of difficulty, scan and show possible numbers, hint and solution for the next value, adjustable window sizes, redo/undo moves, save/load/print puzzles, copy/paste to clipboard.
Solving the whole puzzle at one go is not provided.
http://www.angusj.com/sudoku
4.2
811 KB
Free for private use only
Windows
Pure Sudoku
3
 
Runs as a stand-alone program on a user's computer
4 levels of difficulty, 40 over refreshing backgrounds, 20,000 different sudoku puzzles, auto save game progress, solving whole puzzle at one click.
No scanning and showing possible values, features such as hints, save and load games are limited to the paid version.
http://www.veryfreesudoku.com/
1.52
10.07 MB
Unrestricted freeware
Win 2000 to Vista

Developer's homepage: http://www[DOT]veryfreesudoku[DOT]com/ (obfuscated for yellow WOT rating)

Warning: Downloads from Cnet (Download.com) now require the use of a proprietary installer.

Total Sudoku
2.5
 
Runs as a stand-alone program on a user's computer
Create new puzzle in 3 levels of difficulty; save, open and print games, differentiate correct or wrong numbers entered.
No scanning and showing possible digits in blank cells, no solver provided.
http://www.supersoft.ro/
http://www.supersoft.ro/
1.0
2.0 MB
Unrestricted freeware
Windows 2000 to Vista

 
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Tags

free sudoku, free puzzle game, number placement game, free sudoku solver, free sudoku creator, free sudoku builder, free sudoku generator

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Comments

by Rob (not verified) on 30. April 2012 - 18:23  (92821)

Why isn't SudoGu mentioned?

[Non English link removed]

Or Sudoku Explainer?

http://diuf.unifr.ch/people/juillera/Sudoku/Sudoku.html

Both excellent and imo at least as good as HuDoKu....

by Jojo Yee on 1. May 2012 - 2:49  (92846)

Thanks Rob for the suggestions. Added to the list of "To be reviewed" in the article.

by zheyman on 16. January 2012 - 18:22  (87255)

Hi,

Please try my free online sudoku website: http://www.SudokuByZol.com

What sets it apart from all other sites is its extremely efficient and simple user interface -- both mouse and keyboard.

And it has almost all of the features of your top sites:
5 difficulty levels
Complete/configurable pencil mark support
Optional hints
Allows entry of puzzles from other sources
Printable puzzles

Enjoy,
Zol

by John Pale (not verified) on 10. July 2011 - 18:39  (75148)

In my opinion the best free sudoku software are these three:

Simple Sudoku - http://angusj.com/sudoku/
(very user friendly interface for average users)

SudoCue - http://www.sudocue.net/
(for really advanced users, clean interface, very user friendly)

Xsudo - http://www.sudokuone.com/
(propably the most advanced sudoku generator, solver, helper)

Mostly I use SudoCue.

by Jack_lunn (not verified) on 6. July 2012 - 11:36  (95798)

I've been using SodoCue for a year or two now and I don't think it can be bettered.
Unfortunately it won't work on Mac which I'm gradually going over to.
I have tried a couple of Mac Apps - Susser etc. but they either don't have enough difficulty or the interface is 'messy'
I wish there was a SodoCue for Mac - or does someone know of something similar?

by hobiwan (not verified) on 3. December 2010 - 16:19  (61987)

Thanks for the nice review of my program!

Import/Export: HoDoKu allows importing/exporting puzzle via the clipboard to practically any program that can use the clipboard too.

You can also use this to export puzzles to a text file (although I admit this is clumsy): "Edit/Copy Values" creates an 81 character string with cell values only, "Edit/Copy Candidates" exports all candidates in all cells. Paste it to the text editor of your choice and save it.

by mwalimu (not verified) on 13. October 2010 - 20:36  (59483)

Can anyone recommend a good free sudoku program that supports sudoku variants, including jigsaw (aka squiggly, or polyomino) and size variants?

I currently use one called Sumocue for jigsaw sudoku, but it doesn't have any puzzle generation, and it's lacking a lot of features that I'm accustomed to having in other Sudoku programs (for example, to eliminate candidate values from multiple cells, you have to click each cell separately and remove the value, where other programs such as Simple Sudoku allow you to ctrl-click multiple cells and eliminate the value from all at once). From the list here, KSudoku looks like it would be a good choice if there were a Windows version available.

by mwalimu (not verified) on 15. October 2010 - 17:58  (59596)

I spoke too soon - it turns out there is a way to run KSudoku under Windows, though it requires a rather large emulation package to be installed first. The allure of several sudoku variants was enough for me to think it might be worth it. Unfortunately I found the user interface difficult to work with. And maybe I missed something but as far as I could tell after playing a couple of games on Easy level, it does not appear to have any automation whatsoever for generating and eliminating candidate values - everything must be done manually. This is for practical purposes a dealbreaker for me. I'll play around it a little more to see if I overlooked something, but if this result stands, this won't be staying on my hard drive.

by Dave12 (not verified) on 12. September 2010 - 17:18  (57705)

For someone who wants a really small portable Soduku (92Kb after UPX, Simon Tatham's Portable Puzzle Collection has one called solo as well as other puzzle games.

http://www.chiark.greenend.org.uk/~sgtatham/puzzles/

by Jojo Yee on 13. September 2010 - 13:19  (57732)

That's a good suggestion, Dave. Solo is now added in the review.

by Anonymous on 13. June 2010 - 20:02  (52043)

hi...

another nice free sudoku program is: hodoku

at >> http://hodoku.sourceforge.net/en/index.php

it's a : "a Sudoku generator/solver/trainer/analyzer"

peace.

by Jojo Yee on 21. June 2010 - 8:06  (52577)

Good suggestion... and it's a top pick now.

by Anonymous on 26. March 2009 - 9:41  (18582)

Another suggestion to look at is Simple Sudoku: http://angusj.com/sudoku/

by Jojo Yee on 26. March 2009 - 10:34  (18584)

Just added before I got a chance to read your comments :>)
Thanks a lot, any more?

by Anonymous on 18. December 2009 - 22:58  (38975)

hello...
a very nice free multilingual Sudoku and Wordoku Game, Board Generator, Solver and Printer program is:

sudoku-isanaki 2.6b:

(http://www.tgmdev.be/free_sudoku_generator_solver_isanaki.php)

has many configureable options; author is very responsive to bug fixes and program updates; and much more...

a fav and recommended.

ric (a sometimes bug finder :) )

by Jojo Yee on 19. December 2009 - 2:02  (38980)

Looks good. Will try it out. BTW, I'm also looking at Sudoku that runs on Linux or multi platforms. Give me some time to review and add them.

[Update: Isanaki Sudoku is a good contender and added in the article, while KSudoku and SudokuBan are better programs for Linux.]

by Bob on 26. March 2009 - 8:37  (18578)

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