Blackjack is a game with simple rules that can be learned by almost anyone. It also has a relatively low house edge of 2%, which can be brought down even lower using basic strategy. It is also a popular game to play in online casinos, where the odds can be better than in traditional land-based casinos. However, many players make mistakes that can cost them a lot of money. Some of these mistakes are avoidable, while others are just a matter of luck.

One of the most common mistakes is betting more than you can afford to lose. It is important to establish a budget before you begin playing blackjack and to stick with it. This will help prevent you from getting carried away by winning streaks or chasing your losses.

Another mistake that many blackjack players make is taking too long to decide whether to split or not. The decision to split is based on the value of your hand and the dealer’s card. If you have a pair of aces, for example, splitting is always the best option. This will give you two hands of equal value and increase your chances of winning. However, you should never split a pair of 10s or 5s because they will only get you one more card each and will not improve your odds against the dealer’s up card.

Many players make the mistake of doubling down when they have a strong starting hand. While this might seem like a good way to increase your winnings, it will not work in the long run. It is more likely that you will double down and bust, which will result in a large loss. If you have a strong starting hand of 11, it is usually best to stand instead of doubling.

It is also important to pay attention to the dealer’s up card. Some of the more successful blackjack players are able to beat the dealer’s up card by using the counting system, which is a method of assigning different point values to cards based on their suits and ranks. This will allow you to know when it is the right time to double down or hit.

Some players use a betting progression such as the Martingale to increase their bankroll after losing a hand. This is a dangerous strategy because it can be very expensive quickly. It also requires a large enough bankroll to recoup your losses. It is therefore wise to start with a conservative approach and then gradually increase your bet size as you gain confidence in the strategy. In addition, you should avoid making changes to the table unless it is necessary. This can be done by printing the chart or using flashcards to practice the strategy. This will ensure that you don’t deviate from the recommended strategy and end up making costly mistakes.