Buy bet house edge depends heavily on the commission. A buy bet pays true odds, but the casino charges a vig, often 5%. Buying 4 or 10 can be much better than placing them if the commission is charged only on wins. If the vig is charged upfront, the bet becomes more expensive.
Quick Facts
- A buy bet is a bet that a chosen number rolls before 7.
- Buy bets pay true odds before commission.
- The casino charges a commission, commonly called vig.
- Commission may be charged upfront or only on winning bets.
- Buy 4 and Buy 10 are the most common useful buy bets.
- Buy 5, 6, 8, and 9 depend more on table rules and rounding.
- Always ask, “Do you charge the vig upfront or only on the win?”
Plain Talk
A buy bet is like a place bet with a math adjustment. Instead of paying the standard place-bet payout, the casino pays true odds and then charges a commission.
That sounds small. It is not small.
On 4 and 10, true odds are 2 to 1. A normal Place 4 or Place 10 pays only 9 to 5, which is short. Buying the 4 or 10 can improve the bet if the commission is favorable.
This page covers the house edge. For basic mechanics, read buy bets explained. For the full table, use the craps guide, craps odds, and craps house edge.
The Wizard of Odds craps basics compares buy and place-bet edges, the Wizard of Odds craps appendix supports expected-value calculations, and the Massachusetts craps rules provide formal craps procedure context.
How It Works
A buy bet has two parts:
- The fair true-odds payout.
- The casino commission.
The commission creates the house edge.
| Buy Number | True Odds Payout | Main Issue | Practical Note |
|---|---|---|---|
| 4 or 10 | 2 to 1 | Vig decides value | Often better than Place 4/10 if vig is only on wins |
| 5 or 9 | 3 to 2 | Smaller improvement | Can be useful depending on commission and rounding |
| 6 or 8 | 6 to 5 | Place bet already strong | Often not worth buying unless rules are unusually favorable |
Commission Timing Matters
| Commission Rule | Player Impact |
|---|---|
| Vig charged only on wins | Better for the player because losing bets do not pay commission |
| Vig charged upfront | Worse because you pay commission whether the bet wins or loses |
| Rounded-down vig | Can improve value at certain bet sizes |
| Minimum vig | Can make small buy bets worse |
The phrase “5% commission” is not enough. You need to know when it is collected and how it is rounded.
Craps Table Example
You buy the 4 for $25. The dealer books the bet and marks it with a buy button.
If the 4 rolls before 7, true odds pay 2 to 1, so the gross win is $50. If the casino charges a $1 vig on the win, you receive $49 profit. If 7 rolls first, you lose the $25 and pay no vig under win-only commission rules.
Now compare a $25 Place 4. It pays 9 to 5, or $45 profit. The buy bet can pay more, even after commission.
That is why players often buy the 4 and 10 instead of placing them when the table rules are good.
From the Casino Side:
Buy bets add procedure. Dealers must mark the bet with a buy lammer, track the player position, know whether the commission is collected upfront or on the win, and cut the payout correctly.
The boxman watches commission handling because small errors repeat quickly. If a casino uses win-only vig, dealers must remember to collect at payout time. If the casino uses upfront vig, the commission must be dropped or handled according to house procedure when the bet is booked.
From a game manager’s view, buy bets can be attractive because many players misunderstand them, use awkward bet sizes, or buy numbers where the improvement is small.
Common Mistakes
- Assuming all buy bets have the same edge.
- Forgetting to ask when the vig is charged.
- Buying 6 or 8 without comparing it to Place 6 or 8.
- Using bet sizes that create unfavorable commission rounding.
- Thinking “true odds” means no edge after commission.
- Confusing buy bets with odds bets behind the line.
- Believing a buy bet can overcome the casino edge.
Hard Truth
A buy bet is only as good as the vig rule. True odds are the bait; the commission is where the casino gets paid.
FAQ
What is the house edge on a buy bet?
It depends on the number and commission rule. Buy 4 and 10 can be low-edge when commission is charged only on wins, but worse when charged upfront.
Is buying the 4 better than placing the 4?
Often yes if the vig is charged only on wins. Place 4 pays 9 to 5, while Buy 4 pays true odds minus commission.
Should I buy the 6 or 8?
Usually Place 6 and 8 are already strong. Buying them only makes sense under favorable commission and rounding rules.
What does vig mean?
Vig means commission. It is the fee the casino charges for booking the buy bet.
Is a buy bet the same as an odds bet?
No. Odds bets sit behind line bets and have 0% edge. Buy bets are separate number bets with commission.
Do all casinos charge buy bet commission the same way?
No. Some charge upfront, some charge only on wins, and some use rounding rules that change the effective edge.
What should I ask the dealer?
Ask, “Is the vig upfront or only on the win?” That single question changes the value of the bet.
Deeper Insight
Buy bets are often taught too simply. “Buy the 4 and 10” is decent shorthand, but it leaves out the most important detail: commission rules.
The pure true-odds part of a buy bet is fair. If you could buy the 4 at 2 to 1 with no commission, the bet would have 0% house edge. But casinos do not offer it free. The vig creates the edge.
On 4 and 10, the true-odds payout is much better than the place payout. That gives the commission room to exist while still leaving the buy bet better than placing the same number under many rules.
On 6 and 8, the normal place payout is already close to true odds. A commission can erase the benefit. That is why good craps players do not treat “buy” as automatically better.
The smart comparison is not buy versus nothing. It is buy versus place, at the exact number, with the exact commission rule, at the exact bet size.
Formula / Calculation
Expected Value = (Probability of Win × Net Win After Vig) - (Probability of Loss × Stake)
House Edge = -Player EV / Initial StakeExample: Buy 4 for $25, commission only on win, net win $49 after $1 vig.
Winning combinations for 4 = 3
Losing combinations for 7 = 6
Probability of win = 3 / 9 = 1 / 3
Probability of loss = 6 / 9 = 2 / 3
EV = (1/3 × $49) - (2/3 × $25)
EV = $16.33 - $16.67 = -$0.34 approx.
House Edge ≈ $0.34 / $25 = 1.36% approx.Exact edge changes with vig size, rounding, and whether commission is charged on every bet or only on wins.
Formula Explanation in Plain English
The true-odds payout tries to make the bet fair. The commission pulls it back toward the casino. If the commission is small and charged only when you win, the bet can be relatively cheap. If the commission is collected no matter what, the casino price rises.
Related Reading
Read buy bets explained before comparing them with Place 4 and Place 10 and place bet house edge. For the broader table cost, use craps house edge and the house edge calculator. For dollar impact, test bet sizes with the expected loss calculator and remember the warning in why low house edge does not mean safe.