Blackjack Strategy: When to Double Down

Dean Ryan

March 19th, 2021

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Whether playing in a land-based or online casino, Doubling Down is one of the most thrilling moves in Blackjack. It allows you to double your bet in the middle of a hand in exchange for one extra card. It's a risky gamble, as it usually ends your betting - if you receive a particularly low second card you can't hit again.

This can lead to a more timid blackjack player avoiding the double bet, and more adventurous players making it far too often. It's important to try and strike a balance between sensible safe play, such as using a basic strategy, and risky double downs to maximise your potential winnings.

When to Double Down

Fortunately, basic strategies for blackjack have been meticulously mapped using mathematical probability, designed to tell you exactly when it is best (in the long run) to double down. There are three situations when it's best to double down, explained below.

In all of these situations, you can't go bust and are in the most likely position to finish with a high hand, while statistics indicate that the dealer is in the most likely position to lose the hand.

Hard 9 Against the Dealer's Low Cards

When you are dealt a total of 9, double down when the dealer's upcard shows something between 2 and 6 (any card below 7, not including the Ace). This must be a hard 9; meaning there is no Ace in your hand - so the combinations could be 2-7, 3-6 or 4-5. If you have A-8 (a soft 9), it's best to stand, regardless of what the dealer shows.

Soft 16 To 18 Against the Dealer's Low Cards

If you have an Ace and either a 5, 6 or 7 giving you a 'soft' total of 16 to 18 and the dealer shows a card from 2 to 6, this is a great time to double your bet. With an Ace and a lower card (2 to 4), it is better to just hit, as you are less likely to end with a high hand.

Hard 10 Or 11 Against Any Lower Dealer Card

A hard 10 or 11 puts you in a powerful position - that is, with any two cards, not including an ace, that makes 10 or 11 (2-8, 2-9, 3-7, 3-8, 4-6, 4-7, 5-6). If the dealer has a lower total, it's time to double down.

Splitting in Blackjack

Another popular and basic blackjack strategy is 'splitting'. You are offered the chance to split your two hole cards if they form a pair. The only time you can split a pair occurs after you receive your cards. If you choose to split your pair, your cards will be split into two standard hands as you match the original bet with a second wager. As a result, you now have the chance to double your winnings - or your losses if it does not work out.

While splitting raises the stakes and always provides a little more excitement, you must learn when it is advisable and when it is not. It is best to split in live blackjack and online blackjack if you have a pair of aces or a pair of eights.

Because there are more 10-value cards than any other card in the deck (16 in total), there is a statistical chance of hitting at least one 21 when splitting aces. Also, two separate hands of eight are much easier to play with than one hand of 16, which will very rarely win.

If dealt a pair of 10s, be sure to stick - you are not likely to improve on your hand with anything else. From here on down (in terms of hand value), it's important to note what the dealer has. This is because, statistically, for any given pair, there is a 'right' and 'wrong' option to split when faced with certain cards.

If dealt a pair of nines, the statistically best option is to split if the dealer has a two, three, four, five, six, eight or nine. However, if the dealer has a seven, 10 or ace it makes more sense to stand.

Similarly, if you have a pair of sixes and the dealer has a card between two and six, you should split. Otherwise, take another card. If you have sevens and the dealer has a card between two and seven, you should split - otherwise, you should twist on the original pair.

Similarly, if you have a pair of sixes and the dealer has a card between two and six, you should split - otherwise, take another card. If you have fours and the dealer has a five or six, then split - in any other situation, take another card. If you have either a pair of twos or threes, split if the dealer has any card between two and seven - if not, hit.

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Pay Attention to the Rules

In almost every Blackjack game these strategies for doubling down and splitting should stay true. However, be aware that the rules of Blackjack do vary between casinos, which can affect your decision making. If it's possible to double with three or more cards, then you may find additional hands when you could double down, so pay attention to your total.

On the other hand, you might find situations where the rules say you can't double when the strategy says you should - such as on soft hands (those with an Ace). If you cannot double down when you'd like, be sure to hit instead. To try this double down strategy out in a cash game before hitting a real-life casino, check out the best sites for playing online blackjack!

FAQs - Doubling Down in Blackjack 101

Doubling down in Blackjack allows the player an option to double their wager following receipt of their original two cards. You then get dealt one - and only one - additional card. Then it's you versus the dealer to decide who wins. One major advantage to doubling down in blackjack, is the positive impact it can have on lowering the house edge.

A player doubles down because the situation looks positive so they risk more to win more. As you can control when to double down, this is a powerful tool for the player who can spot the perfect opportunity. Here are a few specific instances where it pays to know where you stand.

Can you Double Down after Hitting?

A player cannot hit and then choose to double down, the double down option occurs only after the initial two cards are dealt by the dealer and the player must then decide whether to go for the double down at that moment or not. The opportunity to double down is limited to this point in a hand.

Can you Split and Double Down?

The player must understand the optimal situations to split and double down. The player can split their cards if dealt a matching pair e.g. 5-5, 7-7, J-J.

The player must cover the second hand with the bet size of their first bet and the dealer deals a second card to complete both hands. A further double down is not usually permitted. Always check the casino rules whether playing live or online, as there are often incentives hidden within the rules designed to encourage players to play.

Should you Always Double Down on 11?

As the player and dealer aim to get as close to 21 as possible to win the hand, the player is in a strong position when holding 11 after being dealt two cards. If the dealer shows a lower card than a 10, it is a good strategy to double down.

If the casino rules dictate the dealer must hit soft 17, you should always double down on 11 no matter what the dealer's up card.

How do you Signal a Double Down?

When looking to double down, there are several things you need to consider. The primary signal of intent is to place a bet or push a stack of chips next to your initial bet. You must ensure this stack equates to the value of this initial bet. When playing with a live dealer, if the addition of chips doesn't prove effective, you can point one finger. This hand signal indicates your intention to double down.