CalcuDoku, Killer Sudoku and Kakuro calculator!

Some of you may have already started playing “the new Sudoku” puzzles that appear in The Times (UK). We call them CalcuDoku or “Square Wisdom“.

It’s an interesting concept, quite similar to Killer Sudoku, but with all four basic arithmetic operations involved. Another change is that repeats within a cage are allowed if possible.

To help out those of you who are starting to like this game, I have prepared a tool that shows you which combinations of numbers can go into a certain cage. All you need to do is plugin the numbers, click “Calculate” and voila!, you get the list of possible options.

Obviously, this same calculator can also be used for Killer Sudoku and Kakuro puzzles.

Here is the calculator:

Cage Value Operation +  *  –  /  no op
Number of cells 2  3  4  5  6  7  8  9
Maximum repeats? No repeats  1  2  3  4  5  6  7  8
Allowed numbers 0  1  2  3  4  5  6  7  8  9

This entry was posted in CalcuDoku, Kakuro, Killer Sudoku, Puzzle variants, Solving tips and tagged , , , , , , , , , . Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.


  1. Sophia
    Posted May 15, 2008 at 6:54 am | Permalink

    I was just wondering how I can pencil in numbers on the online puzzles.


  2. Gaynor
    Posted May 24, 2008 at 9:52 am | Permalink

    I have tried the ones in the Times – with the + – x or / given to you they are quite easy – hope yours are going to be harder, DJ.

  3. Gwyn Morgan
    Posted October 16, 2008 at 6:45 pm | Permalink

    Your calculator for listing the possible combinations is a great help for checking purposes. Would it be possible to modify it to include a maximum number of repeats (2,3 etc.)?
    The list for 23+ in a cage of 6 cells, for example, is very long.

  4. Gwyn Morgan
    Posted October 16, 2008 at 7:39 pm | Permalink

    Sorry about my previous note about the calculator. I must be blind or at least unable to read.

  5. Posted October 16, 2008 at 7:41 pm | Permalink

    No Gwyn, you’re neither blind nor unable to read, it’s just that I amended the calculator about a minute ago, after I saw your question and thought it was a good idea. 🙂

  6. Amy Grace
    Posted December 4, 2008 at 6:20 pm | Permalink

    Thanks for the calculator. I used it to teach myself what the cages could possibly contain when there’s a division operator and a higher number like 9! LOL I couldn’t get that one on my own!

  7. Amy Grace
    Posted December 6, 2008 at 4:01 am | Permalink

    I need a tutorial on how to use maximum repeats. It seems like it can mean one of two things:

    a) The maximum number of times a digit can repeat in the cage. If the cage only overlaps two rows or two columns, the maximum would be two occurrences, but if it twists and turns and crosses more rows or columns, the digit could repeat several times ex) 6*5*2*2*2*2*1…

    or is it

    b) The maximum number of different digits that can show up twice (or more) in the cage. I’ve seen this happen (4*4*3*3*1) but I have no idea how I’d calculate that it could occur.

    Thanks in advance for your help! I love these puzzles now, and I love the calculator!!!

  8. Posted December 7, 2008 at 4:16 pm | Permalink

    Amy, maximum number of repeats is not the max repeats of one number, it is the total repeats of all numbers.

    So in: 6*5*2*2*2*2*1 there are 3 repeats. (three 2s)
    In 4*4*3*3*1 there are 2 repeats. (one 4 and one 3)

    In 3*3*3*2*2*1 there are 3 repeats (two 3s and one 2).

    But that’s looking at it backwards. What you should look at is the shape of a cage, figure out how many numbers could be equal and enter that as the max number of repeats.

  9. Posted December 8, 2008 at 9:21 pm | Permalink

    Hi Calculator enthusiasts,

    I wonder whether you learn Kenken, or even improve your “math”, when you use a calculator? Like bicycling with training wheels, sooner or later you need to drop them if you are going to get the enjoyment from the tool.

    Question. I am working on a method to list numerical candidates that, like some of the better methods for Sudoku, positions the candidates, so they visually stand out. I.e., you don’t have to “read” the numbers.

    Any thoughts would be appreciated.


  10. TwoTimeTom
    Posted February 3, 2009 at 6:37 pm | Permalink

    Calculator Suggestion:

    Lately I’ve been using “cut, copy & paste” in the results window.

    By copying the results before doing another calculation then pasting the previous results below it and repeating for each new calculation I create a list of all relevant information, often labelling each group with a Header to help keep track as the list grows longer.



    I can then go back through the list and delete any entries ruled out or groups solved.

    If the calculator would generate a Header and not erase each result (instead add it to the top of a growing list) along with a radio button to erase the last result (mistaken entry) and another to clear the whole window (start over/new puzzle) I would think it a simple yet powerful tweak to an already useful tool.

    Another idea would be a “no-op” button that returns all 4 (if possible) results at once.

    Thanks for a great tool, I use it all the time.

    Good Luck,


  11. Posted February 12, 2009 at 10:40 am | Permalink

    Tx3, thank you for your suggestions and sorry for responding a little late. I couldn’t agree more with you and so I’ve updated the calculator to provide the extra features you suggested. 🙂

  12. Princess Amy
    Posted February 13, 2009 at 7:36 am | Permalink

    I love Tx3’s suggestion and the new calculator. I may try the puzzles with the limited operators now, even!
    Thanks for this update, djape!

  13. Wayne Courtney
    Posted May 4, 2009 at 7:55 am | Permalink

    This is a wonderful utility. I wish I could put it in my palm centro. Any chance you will publish the programing.

  14. Jean Barker
    Posted October 7, 2009 at 1:12 am | Permalink

    Your new calculator is so long that I have to scroll up and down to use it. The old one was much more user friendly.

  15. Michael
    Posted October 7, 2009 at 9:39 am | Permalink

    I agree with Jean Barker. The old format, though a bit cramped was less cumbersome.

    Perhaps the old format with improved line spacing?


  16. Alan Jones
    Posted October 22, 2009 at 11:48 pm | Permalink

    How about putting the parameters side by side in pairs instead of in a single column – this would lessen scrolling.

    Great calculator, I’d be lost without it.


  17. Michael
    Posted December 3, 2009 at 11:58 am | Permalink

    The “Clear List” button could use an “Are You Sure?” dialog box.


  18. Michael
    Posted December 22, 2009 at 11:59 am | Permalink

    Sorry to tell you this Djape, but today was the first time I was really annoyed with your site.

    I use your calculator to create a needed list and paste & print.

    The “Calculate” and “Clear List” buttons are too close, especially since the calculator is cumbersome and requires scrolling. For several reasons, I have to use a lower resolution that is necessary to avoid scrolling

    The “Clear List” button NEEDS a “Are You Sure?” dialog box, or at least move it to the bottom of the list!

    Good programming protocol dictates this.


  19. Posted December 22, 2009 at 2:57 pm | Permalink

    Michael, I agree the calculator was all over the place, I simply couldn’t find to change it after the last software update which caused it to go funny.

    Anyway, I’ve changed things a little now, and it should be better.

    Let me know what you think.

  20. Michael
    Posted December 23, 2009 at 11:26 am | Permalink

    A *

    Seems like all issues were attended to.


  21. Brenda
    Posted February 21, 2010 at 1:59 am | Permalink

    Can you revise to include 10 in allowed numbers?


  22. JimA
    Posted October 3, 2010 at 8:17 pm | Permalink

    24+, 4 cells, 2 repeats calculates a 7+7+7+3 illegal answer.

    • Posted October 5, 2010 at 3:48 pm | Permalink

      Jim, you are half right, half wrong. “2 repeats” means maximum 3 equal numbers, because no repeats means only 1, “1 repeat” means that a number can be repeated once, 2 repeats, means that a number can be repeated twice (plus the “original”).

      Now, a cage of 4 cells cannot have one number repeated 3 times (“2 repeats”), so in that sense you are right. But this is only a calculator. It is up to you to plug in the numbers the way you want and to you use it to your advantage.

      Hope this helped.

  23. Brenda
    Posted December 16, 2011 at 6:31 am | Permalink

    The calculator is not working for a few days now. I rely on it daily. Thanks for this great resource.

    • Posted December 16, 2011 at 3:59 pm | Permalink

      Brenda, I just checked and the calculator is working for me. You should try clearing up your browser cache or trying with a different browser.

      I am also sending you an e-mail. Please let me know if you fix this problem.


  24. Dave6d6ky
    Posted December 16, 2011 at 5:34 pm | Permalink

    Fails for me as well. I come to the page, and then change nothing (So doing a 2 digit +10): pushing ‘calculate’ does not give any results. Then I try changing some different options (to 600*, 4 digits, 1 repeat) no results.

    I’m using Firefox browser 8, Windows XP. I’ve tried on two different computers. On this one, after seeing your post on clearing the cache, I did that, and restarted Firefox. No difference. I did not reboot.

    I’m not sure using the calculator is worth firing up IE (shudder).

    Wait – I’ve got chrome! . . . Nope – fails there too.

    Let me know if you want me to do anything in particular to narrow anything down.

  25. dave6d6ky
    Posted December 16, 2011 at 5:40 pm | Permalink

    And now we can add Firefox 8 running on Windows 7

  26. Posted December 17, 2011 at 4:38 am | Permalink

    That’s so strange. I checked on different physical computers, using different browsers and it’s working fine.

    I will continue investigating this. In the meantime, if you find that it’s working, please let me know.

  27. Brenda
    Posted December 17, 2011 at 8:45 am | Permalink

    It’s working for me now and I didn’t do anything. Maybe some kind of glitch, but I did try other browsers before reporting the matter to you. Thanks a million.

  28. John
    Posted December 17, 2011 at 2:02 pm | Permalink

    It didn’t work for me for a few days either, but now it does.

    BTW, I love this resource. Thanks for creating it.

  29. Dave6d6ky
    Posted December 17, 2011 at 7:45 pm | Permalink

    Working good again. Thanks!

  30. SHawna
    Posted January 20, 2012 at 5:00 am | Permalink

    I love your calculator!!! Great tool but could you add 10’s… that would make it amazing!

  31. Dave6d6ky
    Posted March 22, 2012 at 8:07 pm | Permalink

    Good evening!

    With the recent changes, I can no longer see the ‘9’ in the allowed numbers checkboxes.

    And – it may just be familiarity – but I liked the look of the old one better.

    Or did something just get in and change my default font??

    • Dave6d6ky
      Posted March 22, 2012 at 8:07 pm | Permalink

      Sorry – using Firefox and Windows XP

    • Dave6d6ky
      Posted March 22, 2012 at 8:14 pm | Permalink

      And – it looked the same on Firefox and Windows 7 (can’t see the 9)

      Using Internet explorer, I can see the 9, but can’t see the right edge of the box.

    • Posted March 23, 2012 at 2:49 am | Permalink

      Dave, thanks for pointing this out. I changed the padding in the cells and it should be better now. Can you see the 9 now?

      I’m sure that all long-term visitors will have some withdrawal issues 🙂 from the old look of the site, but the change is really not that big, and this new look should be easier to navigate and more user friendly. Or so I’ve been told. We’ll see, I can always switch back to the old look with a couple of clicks.

      Thank you again!

  32. dion starfire
    Posted June 30, 2012 at 10:15 pm | Permalink

    It’d be awesome if you could package the calc together as an android app. might even be willing to pay for it.

    • dion starfire
      Posted June 30, 2012 at 10:33 pm | Permalink

      On a related note, I’d love to see an explanation of the calculator’s logic.

      It’s hard to understand how a simple ‘increment and compare’ loop can figure out all the possibilities for a number and operation.

      Even further off down that tangent, this is a great example for teaching the importance of documentation, even for short, simple bits of code. While the code is fairly simple, the objective of each step and loop isn’t that obvious to an outside reader. (I’m not complaining, just saying it’s also a good teaching tool / exercise)

  33. mumdigau
    Posted September 12, 2012 at 4:28 pm | Permalink

    Could you imagine to make this nice calculator a win proggy so it can be used offline?

    • Posted September 13, 2012 at 12:45 am | Permalink

      mumdigau, it is more likely that the calculator will be released as an app for Android and later for iOS. Stay tuned. 🙂

      • dion starfire
        Posted September 28, 2012 at 2:40 pm | Permalink

        The most commonly used app on my android is a kenken game, so seeing this as an android app would be awesome.

        And since an android emulator is freely available for all the major OS’es, you could run the android version on all the major OS’es

  34. jam
    Posted November 19, 2012 at 12:56 pm | Permalink

    hey, looks there is a problem with you facebook integration. i liked this page on facebook 2-3 times but still no calculate button. i comes on one refresh and again vanished on another refresh

  35. Jack
    Posted November 19, 2012 at 2:47 pm | Permalink

    I am trying to figure out how to use this site without joining facebook.

  36. Dave6d6ky
    Posted December 26, 2012 at 8:23 am | Permalink


    A thot on your hiding the ‘calculate’ button plan: Your message says ‘If you can’t see the “Calculate” button, …’ – but it doesn’t tell me where the button should be. I know where it should be – given frequent use of the site – but a newbie wouldn’t know if they’re just looking in the wrong spot, or what.

    Suggestion: Add ‘just above’, or maybe a disabled placeholder.
    I also thought of changing its results – instead of doing the math, it spits out the text about Liking, etc…

  37. Fernando Alves de Castro
    Posted June 17, 2013 at 11:59 am | Permalink

    With the creation of Killer Sudoku 10×10 the zero is also allowed. Can you update your “calculator” in this page with the inclusion of “0” as valid number in a cage? I think that this improvement will be very usefull. What do you think?

    Thanks and best regards,

    Fernando Castro

    • Posted June 17, 2013 at 6:50 pm | Permalink

      You are absolutely right, Fernando. I will do that very soon! 🙂

      • Fernando Alves de Castro
        Posted June 18, 2013 at 1:22 am | Permalink

        Thank you for your willingness to do so.

        Best regards,

        Fernando Castro

        • Posted June 20, 2013 at 7:28 am | Permalink

          Fernando, the calculator has been updated. Please let me know if you find something wrong with it! 🙂 Thanks!

          • Fernando Alves de Castro
            Posted June 20, 2013 at 10:40 am | Permalink

            Thank you very much. I will try to check as soon as possible.

            Best regards,

            Fernando Castro

  38. WizardOfHoz
    Posted June 21, 2013 at 11:16 am | Permalink

    Basic functionality now gone – did some basic 3-cell 11+ calculations and results were all either wrong or incomplete

    • WizardOfHoz
      Posted June 21, 2013 at 12:51 pm | Permalink

      Weird … 1 hr later and now works fine

  39. Fernando Alves de Castro
    Posted June 21, 2013 at 12:22 pm | Permalink

    I found the following discrepancies:

    1) – The calculator runs appropriately with Windows 7 but not with Windows XP. With Windows XP the calculator ignores the 0 (zero);

    2) – You should consider 10 in number of cells because now cage 45 can have 10 cells;

    3) – Maybe number of repeats should be extended.

    Please have a look. Best regards,

    Fernando Castro

    • Posted June 22, 2013 at 2:53 am | Permalink

      1) I think it must be some caching issue. Wait a while until your browser refreshes the content OR press Shift+F5 in your browser.
      2) 45 over 10 cells must be 0123456789 🙂
      3) I really can’t see a cage with a number being repeated more than 8 times. 🙂 Should probably reduce that to 3 or maybe 4. 🙂

      Thanks for your feedback! Please let me know if issue 1) has been corrected or not.

      • Ken
        Posted April 16, 2015 at 8:22 am | Permalink

        I recommend that you define all of your parameters such as Cage Value, Maximum Number of Repeats, etc.

  40. Robert
    Posted September 5, 2015 at 5:45 am | Permalink

    Is it possible to add a “must contain” qualifier?

  41. Chris
    Posted September 13, 2017 at 1:00 pm | Permalink

    Any thought given to add in negative numbers? Or numbers >9?

    • Posted September 14, 2017 at 11:39 pm | Permalink

      Hmm, maybe I will. Which puzzle game do you need the negative numbers for, I wonder?

  42. Brian Kirman
    Posted June 22, 2018 at 8:04 am | Permalink

    Hi DJ

    As a veteran ‘Killer’ freak I remember a page of possible solutions, a sort of matrix. This was great reference to see, for example, the possible combinations in a 5x cage of 23.
    The correspondence above refers to online calculator – which I find slow and also not compatible with the books of yours I buy and use when offline – flying and such.

    Would you be able to drag out the single page matrix from your archives – I remember one was colour, another version was black and white. My copies are now falling apart and beyond photocopying.


  43. Sue
    Posted February 3, 2019 at 7:38 am | Permalink

    I was just trying to calculate 11 – 3 digits, 1-6 with 1 repeat. There were some combinations missing. I already have the non-repeating combinations and am trying to add the repeaters for KenKen. The calculator lists 6 combinations and there should be at least 9
    Thanks for the work you have put into this.

    • Posted February 14, 2019 at 2:18 pm | Permalink

      Hi Sue, I don’t know why you aren’t getting such results. 1 repeat means a number can be repeated once (which means max two occurrences of a number) and “No repeats” means no repeats (max 1 occurrence of any number).

      So, 11+ over 3 digits with no repeats, I get:
      11+ =====

      And 11+, 3 digits, 1 repeat:
      11+ =====

      Hope this helps.

  44. Effie
    Posted July 10, 2019 at 12:17 pm | Permalink

    I know the posts on here are from a very long time ago and I don’t know if you would even be willing to add this feature, but is there a way you could put a “must include” filter? For example I know that my answer must include a 2 or a 4. So if I could only see those results with a 2 or a 4 it would be faster for me to use especially when there are tons of results.

  45. Boudewijn
    Posted January 15, 2020 at 9:57 am | Permalink

    Would it be possible to add an option ‘nr of repeating sets’. So it would rule out triplets but include two pairs: 223335 not, 122337 included.
    Mostly you can have two different doubles, but no triplets.

  46. Dave6d6ky
    Posted December 23, 2020 at 7:30 am | Permalink

    Is there a Donate button anywhere on the site?

    • Posted December 23, 2020 at 11:09 pm | Permalink

      Dave, I really appreciate your wanting to donate. The answer is: no, not at the moment. 🙂 But there will be, a few people have asked for it. I’m really humbled by such requests.

      The best way to donate is by buying my books 😀 It’s good for you and it’s good for me.

      This website is going under major reconstruction, so donate button will be there… in a month or so.

      Have a good one!


      • Dave6d6ky
        Posted December 27, 2020 at 12:04 pm | Permalink

        That HAS to be the quickest month of my life… 🙂
        The button has been pushed. Have a beer or two.

        I thought of buying a book – but – more *stuff*? Nope nope nope

        Thanks for the calculator.

        • Posted December 28, 2020 at 1:45 pm | Permalink

          Thank you, Dave! Really appreciate your donation! Cheers!

  47. Dave6d6ky
    Posted October 8, 2021 at 5:22 am | Permalink

    It’d be nice if the results included the numbers excluded when doing the calculations. For example, if I asked it for a 3 digit 19 without a 0 or 7, the header line could be 19+=====(07)

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