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Sudoku Solver for Android

Latest version 1.93 - 29th of November 2025
Released
£3.49 - Your local sales tax is included in the price.
Your local currency will apply in your locale.

Search for
"SudokuWiki"

Welcome to the project page for the SudokuWiki Solver, an App for Android.

Update 29th November 2025

Fixed the issue with tall phones where the buttons were too low down the screen or invisible. This was due to Android navigation overlays and I needed to account for these and set wider top and buttom margins.

Update 7th November 2025
All solver improvements since June added including Tridagons.
Added in the strong links on the solver for strategies like pointing pairs.
Fixed an issue with layouts that were not scaling if the screen 'density' was not exactly 1.5 or 2. Font on things like the grid coordinates should be reasonable now on some medium/large phones. You may have to dial back the preferences -> font silder.

Update 14th June 2025
Fixed the cell-selected highlight bug when in hint mode 2 or 3
Fixed a bug where 17-clue puzzles could not be graded. Simple <=17 rather than a <17 typo
update to v.190 will roll out today.

Update 7th June 2025
Had some good bug reports. Fixes in 1.89 uploaded tonight are
Grading fixed.
Grader will now ignore strategies that have been deselected but take the score with a pinch of salt as you can only compare it to puzzles with the same strategies deselected.
Hints level should be displayed even on simple steps like clearing candidates off and singles even though there is nothing to hint at.
There was a scoring bug in Chute Remote Pairs. Scores should match online
Some spelling mistakes.

Update 5th June 2025
Attempt three rolled out! Hopefully fixed the problem with the Solution Count and other new bugs from 1.86. Thanks for your patience.

Update 4th June 2025: Latest version now in review and should be rolled out to all devices very shortly. A complete refresh of the solver code as I've made numerous efficiency and optimization changes in the last fifteen months, plus some new strategies. Also the hint mode should be easier to work with as it updates the board instantly, without having to step back and forth. Any new bugs, please let me know.

Unfortunately I loose about 5% of devices with this release as the minimum Android version I can support is now Android 5 (Lollipop, API 21) so anyone still on 4 (KitKat), sorry. But that is more than ten years old. This is required to support Android 15 (API level 35).

Update 26th of March 2024: So it looks like my release of version 1.84 in October 2023 never made it to the Google Play Store - some irrelevant regulatory tick boxes needed to be ticked and I didn't hear about them. So everyone was still on v1.82 which was for a pretty old version of Android and now I'm getting feedback saying the app isn't compatible. Today I have released 1.85 but it is "in review" for up to seven days. Contains all the new stuff from the last six months. Hopefully fix all the problems and the reviews that say it is 'abandonware'. Certainly isn't!

Change Log

Version 1.89, 7th June 2025

Grader will now ignore strategies that have been deselected but take the score with a pinch of salt as you can only compare it to puzzles with the same strategies deselected.
Bug fixes

Version 1.88, 5th June 2025

Updated to Android 15 (API level 35)
All example puzzles have been replaced as the original ones were not all occurring due to changes in the solver.
Added Chute Remote Pairs
Added Twinned XY-Chains
Expanded 'hint mode' and changing hint mode immediately redraws the board.
Internally much code refactored and improved.
Refreshed all documentation. 'Load Example' now works with packed strings where present in the documentation.

Version 1.85, 26th March 2024

Updated to Android 14 (API level 34)
Added Rectangle Elimination and removed Empty Rectangles
Fixed Unique Rectangle Type 3B to also use the third cand in triple
Added Extended Unique Rectangle Type 2
Refreshed all documentation

Version 1.84, 18nd September 2023

Updated to Android 13 (API level 33)
Added Extended Unique Reactangle Type 4
Expanded Hidden Unique Rectangle Type 1 to get more eliminations if symmetrical
Refreshed all documentation

Version 1.83, 22nd April 2022

Added 'Fireworks 'bent set'
Corrected http to https on export links
Changed export to email to general 'share' intent

Version 1.81, 4th March 2021

Added 'Type 5 Unique Rectangles

Version 1.80, 8th January 2021

Added 'Exotic Links' to AIC chains

Version 1.78, 20th March 2020

Updates to the core engine sudoku strategies to version 2.19
New WXYZ algorithm
Added SK Loops
Added URs to Chains
Refresh of the documentation

Version 1.77, 26th November 2017

Updates to the core engine sudoku strategies to version 2.12
Additional captures in Nice Loop strategies
Refresh of the documentation
Checked and replaced example puzzles in case outcomes had changed

See all the update notes at the end of the development page. Approved on Google Play (World-wide) Approved on Amazon.com (seems to be just USA at the moment) Please leave a review. I'd love to hear your feedback. Any issues email me directly - bugs are easy to fix. The build log and progress update on the upgrade version has been moved to a new page.

	Sudoku Solver and Grader This App contains the full 9x9 Sudoku Solver as seen on this website. This includes the Grading feature and Solution Counter.
	364 Practice Puzzles Expanded Samples List: now organized into groups that focus on a specific strategy.
	Smartphone to Tablet Four different layouts have been designed to match the many different Android screen sizes and pixel densities from Smartphones (minimum 480x800) to tablets (1280x800).
	Strategy Guides Included are all the strategy documentation found on this site and each example can be loaded into the solver at a click.
	Puzzle Feed The Daily and Weekly puzzles on this site are now automatically downloaded into the App!
	Customisation The solver board can be set to several color schemes including high contrast colors.
	Favourites Keep track of the puzzles you solve with an almost limitless list entry - each nameable.
	Hints New to our solver - Instead of just "Take Step" use "Hint" to give you the strategy to look for without revealing the whole answer.
	Undo/Redo Better than the website with real 'state' saving - quit, resume any time and a start to end 'back' and 'forward' buttons.

View more Screen Shots

Access to the main features from the home page

Note: Screen shots have been taken from a 480x800 device and shrunk by half. Other devices may have higher screen resolutions and marginally different layouts.

Feedback and Wish-List

You feedback will be most welcome. If you have an idea for a new feature or improvement, don't be shy. Often these can be implemented very quickly. Bugs and other issues most gratefully received.

I am not 100% certain the different layouts groups I've designed will perfectly match all screen densities and resolutions. If you think the solver page or main page looks a little odd - either clipping or too much padding - please let me know. I can add more layouts. Please include the screen information found at the end of the Preferences screen.

~~Practice Puzzles - puzzles that contain specific strategies~~

A future upgrade will contain the Sudoku X and Jigsaw Sudoku puzzles - complete step-by-step solvers including grading and solution count. There will be an editor for entering Jigsaw patterns not found on this site or in my puzzles.

I will explore Camera Capture. This is the only major feature present in the iPhone version that's not in this app. Something I'd like to do but it will require a lot of research.

The 'hint' system could use some more work. I prefer the three levels of hints in the iPhone version and I'll be working towards this in later versions. Currently the hint system reveals the strategy used and colors some cells and candidates, but not the eliminations. This can be too much for some strategies and too little for others. Two levels of hints are now in the App

The app has the ability to call and email program with a link to the website solver and the current puzzle. I'd like to do more and add some kind of Facebook connectivity.

Comments

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CommentsTalk

... by: Freek

Friday 5-Jul-2024

Really awesome site. I’m learning a lot and enjoying sudoku’s much more now.
One thing that really needs to be improved… Searching for “Sudoku Solver” in the play store does not show this app! You might want to change the name of your app slightly. :-)

Andrew Stuart writes:

Good advice!

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... by: Jonathon Schmidt

Friday 12-Jan-2024

I’d enjoy using your app, but I’m finding its set up for android and I have an Apple product. Any suggestions other then buying into android?

Andrew Stuart writes:

I would love to do an Apple version and in fact had one many years ago. But I don't own a Mac nor am I proficient to program one. I'd work with an Apple developer if they wanted to collaborate. But I'd still need a Mac to test and collaborate with.

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... by: Chris

Monday 26-Sep-2022

The 'board' (grid) could be bigger - there is a good deal of wasted space on left/right sides. The info on the 'preferences' screen is:
Screen size: NORMAL 2047 x 1080
densityDPI=420 density = 2.625 scaledDensity=2.625
xdpi=391.885, dpi=391.29675. My phone is Samsung S10+ (big!) and has a 'large font' setting somewhere.

I discovered that I can change cell and number colors, and that has helped with 'high contrast' issues. But the highlights of candidates in cells prior to removal is poor - it's basically a 'purple' highlight on a dark number, so all you see is a blob'. You can infer the number from it's position of course.

I feel like the 'take step' does 'too much' in one go, sometimes. If I see a candidate that can be removed, I tap in the cell and then tap the number to remove it. Assume this is the last candidate. I hit 'take step' and I want that number to be placed in the cell as a solution, and then the next 'take step' I want to evaluate ONLY the impact of that one solved cell, but it seems like the solver also solves any other cells at the same time, which is doing more than I want it to do. Hard to explain; I can explain better in email.

Version is shown as v2.27 sw360.

Andrew Stuart writes:

I'll see if I can add some larger layouts in the next version. Quite hard to test for as there are so many device screens and the emulators are difficult to work with.

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... by: GeorgeSt/GeorgeSt

Sunday 16-Jan-2022

Hi. I just I found your website. It's amazing. To learn python, I wrote such a program (there are 8 algorithms in total that I needed). I tried the first Sudoku and immediately my solution differs from yours. And I can't understand yours. LINK


    [0,0,0,3,7,0,0,5,0],
    [0,0,1,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,6,0],
    [5,6,0,0,2,0,0,0,0],   yours is 1 at D6, why?
    [0,0,0,4,0,0,9,0,1],
    [7,0,0,0,0,0,0,0,0],   my is 1 at F2
    [0,0,0,1,0,9,3,0,0],
    [8,2,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0]

Andrew Stuart writes:

My solver finds both D6 and F2
SINGLE: D6 set to 1, unique in Row
SINGLE: F2 set to 1, unique in Box

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... by: Davek

Thursday 23-Sep-2021

Love the solver and explanations. Thanks

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... by: Wayne Wilkinson

Thursday 3-Sep-2020

I really love the solver on the web page. I am an amateur c programmer and have been working on a sudoku solver using non-brute-force methods. Can you help me find algorithms for some of the advanced techniques? I have already implemented x-cycles using depth first tree search. Thank you very much.

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... by: mohammad

Tuesday 16-Aug-2016

Hello. I am from Iran and I can't purchase sudoku solver app please send this application to my email. I really need it and like it. Thank you very much. Buy!!

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... by: Chris Covino

Saturday 7-Nov-2015

can you alert me when the Android App contains the X Solver variation>? Thank you!

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... by: Felstarr

Thursday 5-Mar-2015

Hi! I just purchased your app on Google Play for my LG G3. Unfortunately, I cannot read the numbers in the actual game grids -- the type is too light and too small. Anything I can do to enlarge and/or bold the font?

Andrew Stuart writes:

Can you go to the preferences screen, scroll to the bottom and tell me what the specificatiions are. For all devices I have tested I have tried to maximise the space used and make the numbers as large as possible. For small devices this might still not be enough. Do you know how to take a screen shot with your device? That would help me see if I can improve it

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... by: tom ahlers

Wednesday 17-Dec-2014

just downloaded your app on my android mobile. went to the daily sudoku and the screen is so small i can't see the numbers. what do i need to do to fix? the app works great on my laptop.
thanks

Andrew Stuart writes:

Try the "Preferences" from the home screen. Can increase the font size.

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... by: Janet

Tuesday 19-Aug-2014

It would be great if this were available for ipads.

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... by: JPF Naperville, IL

Monday 14-Jul-2014

Why are their no extreme puzzles on the daily list of puzzles? also
no unsolvalbles?

Andrew Stuart writes:

The weekly unsolvable IS in the pull down of daily puzzles, but only changes once per week, obviously. I dont have an extreme in the Daily Puzzles set currently, they are not for normal newspaper publication. But I might consider including one in a future update.

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... by: Mike

Tuesday 24-Jun-2014

Hi Andrew,

I find your Sudoku solver extremely useful, thank you for creating it. Does the Android app require internet access to function? Especially the solution count function? I would like to use it on an Android ipad but I don't usually have internet access.

Thanks,
Mike

Andrew Stuart writes:

No, the App only requires internet access to download the Daily Puzzles, which are entirely optional. All solving is done inside the App.

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... by: Joerg

Tuesday 25-Mar-2014

I purchased the app yesterday and I am not able to get a new puzzle into the solver (on Sunday 24-Mar-2013 alain maronani wrote the same), neither from main menu "New Puzzle" nor the solver "Edit Clues". The only way to leave is the original phone back button and then the solver contains the old puzzle. But "Daily Puzzles" work.
It's a SAMSUNG Galaxy GT-S5830i, Android version 2.3.6., resolution: NORMAL 480 x 320, densityDpi= 160, density= scaleDensity= 1.0 xdpi= dpi= 162.56
Your online solver is great and I hope I can use the app, too.

Thanks for any help

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... by: Alan West

Tuesday 17-Sep-2013

This is a good app and I like the hinting system...

For 'accessibility' the app could do with a fontsize +/- for candidates/solutions. On my Nexus 7 tablet (V2) the fontsize for the candidates is too small to read comfortably and even on the Samsung S3 phone, where it is better, I'd still like the option.

Also (but this could be my lack of understanding), for those of us who like to get as far as possible without help, I think it should be a lot easier to manually enter either solved numbers AND (pencil) candidates without mode switching - most apps offer two lines of number keys ('large' and 'small') which is a lot more intuitive!!

Thanks!

Andrew Stuart writes:

I agree, more can be done with font sizes. The problem is that there are so many screen sizes it's a challenge to make it work on all of them. I'll look into a dynamic small/large control.

I'll also look at the control for small/large numbers again. It has been tweaked several times but I am leaning towards a toggle button now.

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... by: Piotr

Saturday 17-Aug-2013

On a SONY S Tablet running Android 4.0.3 the application starts upside down.

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... by: Jose Vega

Thursday 16-May-2013

Hi.

I just downloaded sudokuwiki solver for android. I think I discover a bug or funcionality (?)

Go to the Strategy docs and pickup whatever section. Navagate through it and then change the device orientation. The document will go back to the beginning of that section.

It's frustrating that the candidates popup appears sometimes hiding the area of influence of the chosen cell.

Would be nice if the application could read a sudoku printed using the camera of the device.

Mi Phone is a samsung galaxy II with android 4.1.2

Thanks for the app !

Andrew Stuart writes:

Thanks for the helpful feedback.

I'm not sure what to do about the docs resetting to the top when re-orientated. It is a web page embedded in a browser object. When reorientation occurs all objects, even app forms and screens, are thrown away and redrawn. There is code in place to restore the contents so its seamless to the user, but it doesn’t extend to the position the user was last on a web page. But I'll do some research, you never know.

> It's frustrating that the candidates popup appears sometimes hiding the area of influence of the chosen cell.

That shouldn't occur and I've tested it on several sized devices - I also have a Samsung galaxy II. Can you go to the preferences screen and tell me what is written at the bottom? It will be something about screen sizes etc. That will help me identify what to look for. Also, if you are up to it, a screen shot of the overlapping popup would be awesome! (http://www.makeuseof.com/tag/6-ways-to-take-screenshots-on-android/)
I think you can email from the phone picture library.
I am working on the Camera feature, certainly the last major missing item.

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... by: AStanley

Saturday 30-Mar-2013

I would love to have the solver available for my Nook tablet from Barnes & Noble. As of now the only apps I can have are from them. HELP!!!

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... by: Marcel

Saturday 16-Feb-2013

I now got the app from Google play. So far it looks good, but there is one minor annoyance:
The app only allows portrait orientation. However I have an Asus transformer, and with keyboard attached, it is automatically in landscape mode and so I can't use the app when I have the keyboard attached.
It would nice to have the possibility to run the app in portrait mode, even without new screen layout. E.g. I could live with the app wasting screen space on a tablet because of the wrong orientation.

Andrew Stuart writes:

I will do that. I hadn't appreciated the device being used in that way, I assumed each orientation was equally optional.
Edit: Now in the current version

Thanks for the feedback!

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... by: Ludek Frybort

Monday 11-Feb-2013

I'm happy to see the solver published on Google play!
Now I'm eagerly waiting for and looking forward to an update with Camera Capture included. Until then I'm not buying the app as I have no use for an Android solver without capture. As soon as it's included, I'll wait no more to buy it even if it costs substantially more than the current price then. I'm sure it'll be worth it.

Andrew Stuart writes:

I will be researching Camera stuff very soon. I know Oliver had a lot of difficulty with the iPhone version and not everyone is reporting good success with the capture. But we will see.

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... by: slowofmind

Saturday 9-Feb-2013

It isn't worldwide.
I live in 'Trinidad & Tobago' and also cannot order from Amazon App Store.

However I downloaded the solver from Google Play this morning (about 2 am),
and got it. Will look at it later. I know it will be excellent!

Victor G.

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... by: Marcel

Sunday 3-Feb-2013

Because of geographical reestrictions, I cannot purchase this app. :(
(My Amazon account is registered for Luxembourg)

Andrew Stuart writes:

I am looking at why this is. Peter, below, in South Africa also says the same. It should be world-wide apart from Japan. I'll post a message when I know more about it

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... by: Peter Cherry

Monday 21-Jan-2013

Hi Andrew,

How's the Android Solver coming on?
I can't wait to purchase it!
I've effectively learn't Sudoku using your web solver and I just love it.

Kind regards,
Peter Cherry from South Africa

REPLY TO THIS POST

... by: vikviper

Sunday 2-Dec-2012

So what's going on for the android version?

Andrew Stuart writes:

I've started! And its not going to take a year, promise!

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... by: RoC1909

Thursday 9-Aug-2012

Any word on the Android version or has it turned into vaporware? Kind of curious because I would really like the app.

Andrew Stuart writes:

I want the Android app too. Now the plan is for me to go on an android developer course.

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... by: Roc1909

Wednesday 9-May-2012

Frankly, you could have charged more and I would most likely have no problem with buying it. While I don't have the ability to use the program yet (I am an Android person), the list of features alone makes this something that would warrant a higher cost.

Andrew Stuart writes:

Thanks for the endorsement and the comment. I think it’s a very difficult balance between perception of value and the giveaway prices some apps are set up. I was actually a little worried it was too high. You never know how many decide not to buy. Looking forward to the Android version as well

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... by: RoC1909

Wednesday 9-May-2012

*Patiently waiting for an Android version

*winks

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... by: Don

Wednesday 8-Feb-2012

I would like to beta test the Android version. I have several sudoku apps but none of them really do the job.

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... by: Todd

Friday 9-Dec-2011

I would love to beta test your Sudoku solver for android.

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... by: KV Rajah

Monday 21-Nov-2011

If u can do a solver for Android like http://www.angusj.com/sudoku/, please inform. The only drawback I find in https://sourceforge.net/projects/sudokuopensourc/ is that it does not allow you to create a sudoku from print like Simple Sudoku.

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