Free sudoku apps live off advertising: every interrupted game earns money. To play ad-free in 2026, you have three options: pay for ad removal ($5 to $15 depending on the app), take out a monthly subscription, or pick a one-time purchase app designed without ads, like SudoKoum (€3.99).
Why free apps cut into your games
A "free" sudoku app with millions of players is not a game, it is an ad network. Its revenue depends on the number of ads watched, and the most profitable ad is the full-screen interstitial: the one that lands in the middle of your game, precisely because you cannot ignore it.
That is why the interruption always comes at the worst moment. It is not a bug, it is the product. User reviews from 2025 on the big apps describe ads that keep getting longer, more frequent, sometimes impossible to close, plus data usage that goes through the roof.
Sudoku is hit particularly hard because its players come back every day, often for long sessions. Each regular player represents hundreds of ads per month.
The three business models of mobile sudoku
1. Free with ads
The dominant model, used by Sudoku.com or Brainium's free tier. The genuine upside: trying costs nothing. The structural downside: the more you play, the more you endure. And ad removal keeps getting pricier (the observed price at the market leader went from about $10 to about $15 in 2025).
2. Subscription
Around $5 per month to remove ads and unlock extras. Over a year, a subscription costs more than 10 times the price of a premium app. For a number puzzle, that math is hard to justify.
3. One-time purchase
You try for free, you pay once, you own the game. That is the model of SudoKoum. It is rare because it earns less than advertising, but it is the only model where the app works for the player instead of the advertiser.
How to spot an app that respects your time
- The full price is displayed clearly before installing, with no misleading "free" followed by a surprise paywall.
- The no-ads commitment is in writing, not just absent from the screenshots.
- The free version is actually playable, not a crippled demo that forces your hand.
- No subscription hidden behind a "3-day free trial".
What SudoKoum does
SudoKoum follows the third model and takes the logic all the way: even the free version contains no advertising. The download is free, and a single €3.99 purchase unlocks everything, for life. That commitment is written into our manifesto, so it cannot be quietly walked back.
To compare prices and features across the big apps in detail, see our dated, verified comparison.
Guide published by Kaizen Suru, maker of SudoKoum. Prices and practices observed in July 2026 on store listings and public user reviews.