Four By 21
Four columns. One goal: 21.
Free · Designed for iPad. Not verified for macOS.
Four columns. One goal: 21.
Four By 21 is a fast-paced card puzzle where blackjack strategy meets solitaire. Stack cards into four columns, make 21, clear space, and race the clock.
Use HOLD wisely, build streaks, and chase high scores without busting.
How to Play
- Place Your Cards: Tap one of the four columns to place your active card.
- Reach 21: Make a column total exactly 21 to clear it and score points. Aces count as 1 or 11, and face cards count as 10.
- Watch the Busts: If a column goes over 21, you bust. You only get 5 busts per round before it is game over.
- Beat the Clock: You start with 70 seconds. Every time you clear a column, you earn bonus time to keep the game alive.
Key Features and Scoring Strategies
- The Hold Slot: Tap the Hold zone to save your active card for later. Swap it out when the right moment arrives to save a column or score a combo.
- Streak Multipliers: Chain together rapid clears without mistakes to build your streak multiplier and drive up your score.
- 5-Card Charlie: Play five cards in a single column without busting to clear it instantly for a 600-point reward.
- Lucky 7-7-7: Stack three 7s to hit 21 and earn a 400-point bonus.
- Board Clear Bonus: Clear all four columns to sweep the board and trigger a big score boost.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Sound effects adjustments
The developer, Alexander Harm, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
- Usage Data
- Diagnostics
Data Linked to You
The following data may be collected and linked to your identity:
- Identifiers
- Usage Data
- Diagnostics
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Alexander Harm
- Size
- 23.4 MB
- Category
- Card
- Compatibility
Requires iOS 15.6 or later.
- iPhone
Requires iOS 15.6 or later. - iPad
Requires iPadOS 15.6 or later. - iPod touch
Requires iOS 15.6 or later. - Mac
Requires macOS 12.5 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Contains
Advertising
- Copyright
- © 2026 Alexander Harm