If both you and the dealer get blackjack, it is a standoff (tie). If both you and the blackjack dealer have an ace and a picture card, you will not be paid 3 to 2. Instead, the dealer will simply leave your bet in the box, just like if both you and the dealer had e.g. 18.
Typically, if you are dealt a blackjack (two cards adding up to 21), your bet will be paid one and a half times.
However, if the dealer has a blackjack as well, then the value of your hands is exactly the same, therefore it is a tie.
Note: if you get a blackjack and the dealer has 21 (with three or more cards, e.g. a queen, a six, and a five), then your hand is higher and the payout will be 3 to 2.
Either way, a blackjack is the highest possible hand and when you do have it, you cannot lose — the worst case scenario, as explained above, is a tie with the dealer.
Even money
If you get blackjack and the dealer shows an ace, the dealer may offer “even money”.
If you accept, then the dealer will pay your bet one to one.
At first glance, this sounds like the most sensible decision — you can’t lose. However, statistically you should never take even money.
In the long run, you’ll win more money if you simply let the dealer take a card; most times, the dealer will not get a blackjack and the payout will be 3 to 2.
That being said, if you play once in a while and want the more conservative option, especially if you’re about to cash out, go for it.
Who wins in blackjack if you tie with the dealer?
Assuming you did not put any chips on the side bets, then you will not win anything if there is a tie.
You will not lose, either. In a tie, both hands have the exact same value, so it’s as if the hand was not played — you get to keep your chips.
You then have the option to either keep the original bet in the box, and wait for the following hand, or remove the bet (or increase/decrease it).
If there is another tie, same again — you keep your chips and wait for the following deal.
What happens if you and the dealer bust?
If both you and the dealer bust, you will lose your bet. Any player bet that goes over 21 loses and will be removed by the blackjack dealer, regardless of the dealer’s cards.
On the other hand, if the dealer busts, and you still have your chips on the blackjack box, you will always win, regardless of your score.
If you had a deuce and a six, and chose not to take any more cards for whatever reason, and the dealer went over 21 — you would be paid even money even though your total score would be very low.
This is why basic strategy (a basic way to lower the house edge with no card counting, shuffle tracking, or anything like that) suggests you do not take any card if the dealer has a weak card, such as a six, even if you only have, say, 13.
Again, if the dealer busts, it doesn’t matter whether you have 11 or 20 — you win.
For the actual strategy (what to do depending on your cards, and the dealer’s), you can have a look at the table below.
It refers to blackjack played in the UK and it doesn’t cover all scenarios, but it gives you a pretty good idea of what basic strategy looks like.

Keep in mind: any blackjack strategy that doesn’t involve some kind of cheating cannot win in the long run.
Casinos are a business and anything that lowers the house edge to the point where the player has an advantage, even if tiny, will not be allowed.
Basic strategy allows you to lower the house edge significantly, but not completely, and you’ll never get kicked out for using it…