Casino & Table Games

Blackjack rules ace

Value

1 or 11 points per ace⁴²

Natural blackjack

Ace plus any 10-point card as the first two cards⁴

Split aces limit

One card per ace; a ten on a split ace counts as 21, not blackjack³⁶

Key points

• An ace counts as 11 when the hand is 21 or below; otherwise it counts as 1.⁴¹
• When a pair of aces is split, most casinos deal only one additional card to each ace, and you cannot hit or double afterwards.³
• A ten-value card on a split ace makes 21 points but is not treated as a natural blackjack.³⁶

Where this term is used

• Blackjack

Not the same as

• Splitting aces in blackjack — the specific action of splitting a pair of aces, whereas 'ace rules' covers the broader value and handling rules including soft totals and natural blackjacks³⁵⁶

Related terms

Sources

1. Basic Strategy for Some Simplified Blackjack Variants - arXiv arxiv.org Confirms ace value rule (1 or 11) and basic strategy context.
2. arXiv:math/0412311v1 [math.OC] 15 Dec 2004 arxiv.org Supports ace valuation and definition of ace rules in blackjack.
3. Blackjack en.wikipedia.org Provides the common rule for splitting aces and the ten-on-split-ace result.
4. Blackjack wizardofodds.com Primary source for ace value, natural blackjack definition, and ace rules context.
5. Blackjack - Basic Strategy (General) wizardofodds.com Distinguishes split-ace action from broader ace rules.
6. Play Online Blackjack Now! For Real Money or Free wizardofodds.com Details split-ace limitations and that a ten on a split ace is 21, not blackjack.

Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.