Blackjack 21

Play blackjack. Learn the decisions. Train the count.

Blackjack 21 combines a clean, fully playable card game with practical tools for learning basic strategy and card counting. There are no ads and no account is required.

PLAY YOUR WAY
• Choose 1, 2, 4, 6, or 8 decks
• Set dealer soft 17, double after split, resplitting, late surrender, and shuffle depth
• Practice split, double, surrender, and insurance decisions
• Review hand history with every decision graded: what you played and what strategy recommends
• Track your performance and strategy accuracy
• Light and dark themes, plus a four-color deck for easier reading
• Designed for Android phones and tablets

LEARN BASIC STRATEGY
• Use strategy charts matched to your selected rules
• Drill hard totals, soft totals, pairs, or mixed hands
• Focused practice saves the hands you miss and brings them back until you get them right three times in a row
• Get immediate feedback with concise probability-based explanations
• Your training progress is saved between sessions
• Learn eight card-counting systems (Hi-Lo, KO, Hi-Opt I and II, Omega II, Red 7, Zen Count, and Wong Halves) plus practical bankroll fundamentals

GO FURTHER WITH PRO
One optional lifetime Pro purchase unlocks:
• Live running and true counts for all eight systems, with Show, Hide, or Quiz me modes
• Strategy basis: play and grade by basic strategy or count-adjusted strategy, with index-deviation and insurance guidance
• Bet suggestions from preset or custom bet ramps
• Speed count, Deck countdown, Deviations, and Bet ramp drills
• Bankroll calculator

PRIVACY AND ACCESS
• No advertising or cross-app tracking
• No account or sign-in
• Core gameplay and training work offline
• Optional anonymous usage data helps us see which features are useful. It is on by default and you can turn it off anytime in Settings
• Optional bug reports and automatic crash diagnostics help us improve reliability

Blackjack 21 simulates casino card play for entertainment and training only. It does not offer real-money gambling, prizes, wagering, or cash-out.

Recent changes:
• Choose 1–1,000 hands in Basic strategy and Deviations, with more varied practice.
• Set hands per hour in the Bankroll calculator.
• Bet Ramp hints and strategy charts match your drill.
• Swipe down to close Settings sheets and pickers.
• Fixes for saved deck counts, kept bets, custom ramps, and training timers.
• Clearer layouts, smoother shuffles, and improved purchase and restore handling.