Side Bets promise big payouts for small stakes, and they can be hard to resist. But it helps to understand the math behind this before you toss extra chips into those side circles. You will make much smarter decisions at the table when you see the numbers.
A side bet is a secondary wager placed alongside your main game bet. It is independent of whether you win or lose the base game. Side bets typically offer higher payouts, but the house edge on them is almost always much higher than on the base game itself.
The House Edge: Base Game vs. Side Bets
The house edge is the percentage of each bet the casino expects to keep. Here’s where the gap between base games and side bets becomes very clear.
| Blackjack (basic strategy) | 0.5% |
| Baccarat (banker bet) | 1.06% |
| Roulette (European) | 2.7% |
| Roulette (American) | 5.26% |
| Blackjack – Perfect Pairs side bet | 6% – 11% |
| Blackjack – 21+3 side bet | 3.2% – 13.4% |
| Baccarat – Tie bet | 14.36% |
| Roulette – Five-number bet | 7.89% |
| Slots – Bonus side bet | 10% – 15% |
A skilled blackjack player using basic strategy is only giving up half a percent on every hand. But the moment they add a Perfect Pairs side bet, the house edge on this portion of their money jumps to as high as 11%. This is 22 times worse.
How Combined Bets Affect Your Overall House Edge
Your overall house edge becomes a weighted average of both bets when you combine a base game bet with a side bet. This means the size of each bet is as important as the edge on each one.
The formula looks like this:
Combined Edge = (Base Bet × Base Edge + Side Bet × Side Edge) ÷ Total Wagered
Let’s put real numbers to it. Say you’re playing blackjack and you bet $20 on the base game and $5 on the Perfect Pairs side bet. Your total wager is $25.
- Base game contribution: $20 × 0.5% = $0.10
- Side bet contribution: $5 × 8% = $0.40
- Total expected loss: $0.50
- Combined house edge: $0.50 ÷ $25 = 2.0%
You just quadrupled your effective house edge by adding a $5 side bet to a $20 hand.
A Side-by-Side Comparison
Let’s compare two players over 200 hands of blackjack, each betting $20 per hand on the base game.
| Player A – No side bet | $20 | $0 | $20 | $20 |
| Player B – $5 Perfect Pairs | $20 | $5 | $25 | $100 |
| Player C – $10 Perfect Pairs | $20 | $10 | $30 | $180 |
Player A sticks to basic strategy and loses only $20 over 200 hands in expectation. Player C, adding a $10 side bet each hand, is expected to lose $180. That’s nine times more despite only adding $10 extra per hand.
Why Side Bets are Appealing
Casinos are very good at making side bets feel worth it. Here’s how they do it:
- Big payout numbers look exciting. A 100:1 payout sounds incredible. But the house still wins in the long run if the odds of hitting this payout are 200:1. The payout is generous enough to keep you interested, but not generous enough to overcome the built-in edge.
- Small bet sizes feel low risk. Dropping $5 on a side bet when your main bet is $25 feels insignificant. But as shown in the table above, this small bet can multiply your expected losses dramatically over a session.
- Wins are memorable, losses are not. A side bet that pays out can feel like a bonus. When it loses, it feels like a small miss. Our brains are wired to remember the wins more vividly.
The Return to Player (RTP) Perspective
RTP is simply the flip side of house edge. The game returns $95 on average if the house edge is 5%, and the RTP is 95%.
| Blackjack (basic strategy) | 0.5% | 99.5% |
| 21+3 Side Bet | 7.8% | 92.2% |
| Perfect Pairs Side Bet | 8.0% | 92.0% |
| Baccarat Tie Bet | 14.36% | 85.64% |
The casino keeps more money when you move further from the base game. A blackjack player with basic strategy can expect to get back $99.50 for every $100 played. A player relying heavily on side bets might only see $85 to $92 back.
Are There Any Side Bets Worth Playing?
Not all side bets are equally bad. A few have relatively low house edges, especially in games where card counting or other strategies can shift the odds.
- Lucky Ladies (Blackjack): House edge around 17-25% in standard play, but it becomes one of the most card-counter-friendly side bets available.
- Dragon Bonus (Baccarat): House edge around 2.65% on the player side, which is much lower than most side bets and comparable to some main game bets.
- Royal Match (Blackjack): House edge between 3.7% and 10%, depending on the number of decks. Lower deck counts are more favorable.
The lower the house edge, the more reasonable the side bet. Anything above 5-6% should be treated with caution.
How Variance Can Change the Picture
House edge tells you what to expect on average. Variance tells you how bumpy the ride will be getting there.
Side bets are high-variance bets. This means you will see long losing streaks broken up by occasional large payouts. The base game is lower variance. Your results are more predictable.
When you combine the two, you get:
- A higher average expected loss (due to the elevated house edge)
- A more volatile session (due to the high variance of the side bet)
This is why some recreational players enjoy side bets. The possibility of a large unexpected win adds excitement. But this excitement comes at a cost from a mathematical standpoint.
Practical Tips Based on the Math
You do not have to avoid all side bets forever. But you need to make informed choices. Here’s what the math suggests:
- Keep your side bet small relative to your base bet. If your base bet is $20, limit your side bet to $1 or $2 to keep its impact on your combined house edge very small.
- Stick to lower-edge side bets. Dragon Bonus in baccarat or Royal Match in single-deck blackjack offer better odds than bets like the Tie or Perfect Pairs.
- Set a side bet budget separately. Treat your side bet money as entertainment spending, separate from your main bankroll.
- Learn basic strategy first. Squeeze the house edge down to 0.5% on your base game to have a much stronger foundation before adding any side action.
Conclusion
Side bets almost always carry a higher house edge than the main game. Adding these bets can increase your overall expected loss per dollar wagered. A blackjack player using basic strategy can keep the house edge as low as 0.5%, but adding a modest side bet can push their effective edge past 2%, 3%. In fact, it can be higher depending on the bet and its size. This does not mean side bets are off limits. It means bets should be chosen carefully, sized wisely, and understood fully before being placed.