# Killer Sudoku! — Logic puzzles for your brain

> Logic puzzle game combining Sudoku rules with region sum constraints. (iPhone/iPad app by Sarah Pierce.)

- Source: https://appshunter.io/ios/app/killer-sudoku/id437747279 (this page in markdown: same URL + `.md`)
- Developer: [Sarah Pierce](https://appshunter.io/developer/406813189)
- Category: Games, Education, Puzzle
- Price: Free with in-app purchases
- Rating: 4.80/5 from 2,010 App Store ratings · 310 written reviews indexed
- Age rating: 4+
- Requires: iOS 9.0 · 13 MB
- Languages: American English
- Released: 2011-05-26
- Data updated: 2026-08-28
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/killer-sudoku/id437747279/reviews.md

## What is Killer Sudoku!?

Even better than killer sudoku on paper!

Killer sudoku is a popular variation on classic sudoku puzzles. To complete a puzzle you must fill the board with numbers that obey traditional sudoku rules AND make each outlined region sum to a specific value. The grid begins blank, but these rules give you all the information you need to solve the puzzle!

Solving a killer sudoku puzzle requires a lot of notes, so we worked hard to make the note entry features in this app perfect. A dedicated note keypad and the ability to select multiple squares makes entering notes fast. You can even make combination lists that float above the puzzle and can be rearranged on the screen! Cross out combinations from your lists as you rule them out.

Our interface is so good, you may prefer it to doing puzzles on paper.

Features: 
- Dual keypads -- no tedious toggling between note and answer mode 
- Multi-square note entry -- a huge timesaver 
- Handy combination lists -- can be rearranged on the screen for easy comparison
- Quick sum button -- add all selected sum labels instantly 
- Quick combination list button -- list all combinations fast by dragging over the desired region
- Built-in mini calculator -- do even long sums easily
- Undo & redo buttons -- step back through your changes to fix a mistake
- Mistake highlighting option -- don't let mistyped entries from set you back
- Auto note option -- automatically remove trivially eliminated notes when you enter an answer
- Two color schemes -- a neutral newspaper color scheme and a rainbow color scheme
- Puzzle gallery -- scroll through puzzles and see your progress instantly
- Comes with 10 free puzzles for testing, and over 3,000 puzzles available for purchase

We made this app free so that you can test it without having to buy anything. It comes with ten free killer sudoku puzzles--two puzzles in each of the five levels. There are also more than three thousand puzzles available to purchase, but the ten free puzzles might just keep you busy for a long time :)

All our killer sudoku puzzles have a unique solution.

## Key features

- Dual keypads for notes and answers
- Multi-square note entry
- Rearrangeable combination lists
- Quick sum and combination list buttons
- Built-in mini calculator
- Undo/redo functionality
- Mistake highlighting

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Easy puzzle pack #1 | $0.99 | one-time |
| Medium puzzle pack #1 | $0.99 | one-time |
| Hard puzzle pack #1 | $0.99 | one-time |
| Extra hard puzzle pack #1 | $0.99 | one-time |
| Impossible puzzle pack #1 | $0.99 | one-time |
| Impossible puzzle pack #2 | $0.99 | one-time |
| Mega puzzle pack | $4.99 | one-time |
| Mega puzzle pack 2 | $4.99 | one-time |
| Mega puzzle pack 3 | $4.99 | one-time |
| Mega puzzle pack 4 | $4.99 | one-time |


## What do users think of Killer Sudoku!?

Overall sentiment: positive

**Pros**

- 👍 Excellent user interface
- 🚀 Smooth gameplay
- 💡 Helpful tools (calculator, combo lists)
- 🔒 No ads or in-app purchases
- 👍 Intuitive controls (separate keypads)

**Cons**

- 🐛 Occasional crashes or bugs
- 🔍 Limited free puzzles
- 💰 Paid puzzle packs can be expensive

**Commonly reported bugs**

- Puzzle progress not saved correctly
- Landscape mode not working after update
- Incorrect puzzle information (cage sums)

**Most requested features**

- Ability to reset/replay completed puzzles
- Option to disable auto-note removal
- More free/affordable puzzle content
- Highlight cells with same numbers
- Landscape mode support for all screens

## Recent user reviews (10 of 310)

All indexed reviews: https://appshunter.io/ios/app/killer-sudoku/id437747279/reviews.md

### 5/5 — Addictive!

*2026-08-26, version 4.1*

I find that the puzzles can be variable in difficulty in a strange way. Sometimes the hard ones are impossible and sometimes the impossible ones are easy. But in some ways that adds to the pleasure.

### 5/5 — By far, the best killer sudoku ios app

*2026-07-30, version 4.1*

It's a bit basic but that's all I want. I don't want unnecessary or over engineered UI elements.

On that note, UI is the best I've found for entering numbers, and the solution generator and calculator are nice additions. 

If I had to criticise anything:
• Tapping to rule out potential solutions needs to be precise. If you accidentally tap between two solutions you can somehow select the actual square below the number pop up, deselecting the boxes you had highlighted. This is my biggest annoyance.
• The font size used for the sum of selected boxes is a bit small. It's not an issue during the day but if in bed with a low screen light, my eyesight can struggle to read it. For example, [132] was a problem last night. 
• The calculator uses the same number buttons as at the bottom but there's no zero, so they added it to the calculator pop up. I'm used to it now but it's a bit jarring. I appreciate this was to keep the UI uncluttered and calculator popup small (and they're movable). I'm just wondering if there was a more elegant solution. A

Anyway, I've run out of all the puzzles (including the add-on packs), but there are so many I frequently go back to completed ones, clear them and try to beat my times. 

I've turned all hints & error checks off but you can turn them on in an instant if you want to check something / where you went wrong. When I do this, I'll clear it and back out, do a different one and come back to it later. Got to have personal integrity when it comes to killer sudoku.

### 5/5 — Definitely great value

*2026-07-28, version 4.1*

What makes this sudoku special is the quality of the puzzles, the tools available to help take the game to the next level and no ads. It starts with encouraging easy levels but by the time you work up to the impossible levels, you have become areal expert. Highly recommended.

### 5/5 — Best of all

*2026-07-26, version 4.1*

Have played most Killer Sudoku apps and their so called 'Expert' levels are nothing of the kind: 5 or 6 numbers filled in within 2 or 3 minutes. This app is completely different - and the dual keyboard and multiple square pencil fill in tool is beautiful. Congrats to the developers. I've just finished all of the Impossible levels so am leaving this review in case I can't reload the app.

### 5/5 — Challenging puzzles, no ads

*2026-06-30, version 4.1*

This is the level of difficulty of puzzle I’ve been looking for. Really excellent. Handy calculator and combinations tools.

### 5/5 — My forever game

*2026-06-19, version 4.1*

Killer sudoku is awesome, and this version is the best because it lets me focus on strategy rather than too much math. By highlighting cells, it will add them for me. If I want to know all possible combinations, it will show me. When I have done all puzzles, I download the game again and start over. This is the perfect bathroom companion game.

### 5/5 — Definitely great value

*2026-06-08, version 4.1*

This is by far my favorite killer S. Easy to use, no ads, different levels of puzzles, lots of them, great extra features but not intrusive, worth every penny.  I especially like the extra features which help with the math to solve some super challenging levels. SO satisfying! I have now bought a second bumper pack.

### 5/5 — Very addictive

*2026-05-08, version 4.1*

A great little package! Have completed it and was then able to reset and start over!

### 5/5 — Best Sudoku

*2026-05-05*

I have used a few different killer sudoku apps and this is by far the best. Definitely worth the small amount of money to buy a huge number of extra puzzles.

### 4/5 — Highlighting specific numbers

*2026-03-12, version 4.1*

Would like to be able to highlight all the 1s for example, added & in notes to see where the gaps are

## Frequently asked questions about Killer Sudoku!

### What is Killer Sudoku?

Killer Sudoku is a logic puzzle that builds upon classic Sudoku. In addition to the standard Sudoku rules (each row, column, and 3x3 box must contain digits 1-9 without repetition), you must also ensure that the sum of the numbers within each outlined region equals the small number printed in the corner of that region.

### What are the key features of this Killer Sudoku app?

The app boasts dual keypads for seamless note and answer entry, multi-square note selection for speed, and customizable combination lists. It also includes a quick sum button, a built-in calculator, undo/redo options, mistake highlighting, and auto-note elimination.

### Is this app free to play?

Yes, the app is free to download and test. It comes with ten free Killer Sudoku puzzles, offering two puzzles across five difficulty levels. Additional puzzle packs are available for purchase.

### What devices is this app compatible with?

While specific device compatibility is not detailed, the app is designed for mobile use and offers features like color schemes and a rearranged interface that suggest adaptability to various screen sizes and touch interactions.

### What are the benefits of playing Killer Sudoku?

Playing Killer Sudoku enhances logical reasoning, problem-solving skills, and concentration. The app's features, such as note-taking tools and mistake highlighting, are designed to make the solving process more efficient and enjoyable, potentially improving your ability to tackle complex puzzles.

## Version history (last 5 releases)

### 4.1 — 2020-06-20

- Landscape is back on iPad! 
- Bug fix for "Puzzle complete" problem

Thank you to everyone who emailed with bug reports and feedback about the recent update. Your emails help me get things fixed faster! Please let me know if you have any issues with the latest version. Best, Sarah

### 4.0 — 2020-06-18

What's new:
- Updates to meet new App Store requirements
- Improved support for all screen sizes
- Bug fixes

Thanks so much to everyone who has sent me feedback! Your comments are so, so helpful, and I really appreciate when people take the time to send in bug reports and other ideas. If you notice any new issues please let me know. I hope you enjoy the update! -Sarah

### 3.6 — 2016-02-04

Bug fixes for auto note.

New in the last version, in case you missed it:
- Cross out combinations from a combination list: just tap to cross out, and tap again to undo
- New auto note feature: automatically removes eliminated notes when you enter an answer
- No timer option: hides the timer and removes your finish times from the puzzle list
- Bonus #160 no longer crashes. Thanks to the users who emailed about this! 

I am really excited about the new features in this version! In particular, crossing off combinations from a list is extremely handy. I find the auto note feature a bit TOO useful sometimes, but for the harder puzzles it's a great way to remove some of the busywork so you can focus on the more complicated strategy. The new auto note and timer options can be found by pressing the button with a light bulb on it. 

I hope you guys enjoy the update, and thanks again to everyone who sent feedback! Happy Puzzling  --Sarah

### 3.5 — 2016-02-01

- Cross out combinations from a combination list: just tap to cross out, and tap again to undo
- New auto note feature: automatically removes eliminated notes when you enter an answer
- No timer option: hides the timer and removes your finish times from the puzzle list
- Bonus #160 no longer crashes. Thanks to the users who emailed about this! 

I am really excited about the new features in this version! In particular, crossing off combinations from a list is extremely handy. I find the auto note feature a bit TOO useful sometimes, but for the harder puzzles it's a great way to remove some of the busywork so you can focus on the more complicated strategy. The new auto note and timer options can be found by pressing the button with a light bulb on it. 

I hope you guys enjoy the update, and thanks again to everyone who sent feedback! Happy Puzzling  --Sarah

### 3.4 — 2015-06-25

- Two new megapacks! That's over 1600 new puzzles!
- Bigger keypads on long format iPhones (5, 6, and 6+)

Thanks so much to everyone who emailed with feedback and left reviews. I am thrilled that people like the app enough to have played through ALL the puzzles and need more. Happy sudokuing :)   -- Sarah

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## More apps by Sarah Pierce

- [Conundra](https://appshunter.io/ios/app/conundra/id406813186)
- [•sudoku](https://appshunter.io/ios/app/sudoku/id441153803)
- [Sudoku School!](https://appshunter.io/ios/app/sudoku-school/id441158805)
- [*SUDOKU](https://appshunter.io/ios/app/sudoku/id463774685)
- [Word Search +](https://appshunter.io/ios/app/word-search-plus/id464846439)

All apps by Sarah Pierce: https://appshunter.io/developer/406813189

## Related topics

[killer sudoku](https://appshunter.io/ios/topics/killer-sudoku) · [killer bean unleashed](https://appshunter.io/ios/topics/killer-bean-unleashed)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-28.*