Craps Prop Bet Keys: Dealer Payout Math Explained

Dealer math · Horn and C&E keys · Standard 30/15 paytable

Prop-bet keys are mental shortcuts dealers use to calculate multi-part proposition payouts. They work only when you know the paytable, distinguish profit from total return, and account for the losing pieces of a split wager.

“To 1” versus “for 1”

Displayed payout	$1 profit	Winning $1 returned	Total value
30 to 1	$30	$1	$31, sometimes called 31-for-1
15 to 1	$15	$1	$16, sometimes called 16-for-1
7 to 1	$7	$1	$8, sometimes called 8-for-1
4 to 1	$4	$1	$5, sometimes called 5-for-1

A dealer key often starts with the total return, then subtracts the losing pieces while leaving the winning unit working. A player asking “How much did I win?” usually wants net profit. State which number you are calculating.

Straight-up 2, 3, 11, and 12

Total	Standard profit	Return including wager	$6 example
2 or 12	30 × bet	31 × bet	$180 profit; $186 including wager
3 or 11	15 × bet	16 × bet	$90 profit; $96 including wager

C&E key

A standard C&E splits the total equally between Any Craps and 11. With a $2 C&E, $1 is on each side.

Result	Winning component	Losing component	Net profit on total C&E
2, 3, or 12	Any Craps wins 7 × half	Eleven half loses	3 × total bet
11	Eleven wins 15 × half	Any Craps half loses	7 × total bet

Examples: a $2 C&E nets $6 on craps or $14 on 11. A $10 C&E nets $30 on craps or $70 on 11. A $5 C&E requires $2.50 components; many dollar games will not accept or will handle that fraction differently, so do not assume the key applies.

High-Low key

High-Low splits equally between 2 and 12. If the total wager is B, each side is B/2. One side wins 30 units while the other loses one:

net profit = 29 × half the total bet = 14.5 × total bet

For a $20 High-Low, $10 is on 2 and $10 on 12. A winning side earns $300; the other $10 loses, leaving $290 net profit. The winning $10 wager remains yours.

Horn bet key

A proper Horn bet divides into four equal units on 2, 3, 11, and 12. For a $4 Horn, each number has $1.

Horn result	Winning profit	Three losing units	Net profit	Key on total Horn
3 or 11	15 units	−3 units	12 units	3 × total bet
2 or 12	30 units	−3 units	27 units	7 × bet − ¼ bet

A $4 Horn therefore nets $12 on 3/11 or $27 on 2/12. A $20 Horn nets $60 on 3/11 or $135 on 2/12.

Horn High: general method

Horn High uses five equal units: one on each Horn number plus an extra unit on the called number. A $5 Horn High 12 is $1 each on 2, 3, and 11, and $2 on 12.

$5 Horn High 12 result	Calculation	Net profit
12 (called high number)	$2 × 30 − $3 losers	$57
2 (other high number)	$1 × 30 − $4 losers	$26
3 or 11	$1 × 15 − $4 losers	$11

For Horn High 2, the same rows apply with 2 and 12 exchanged. If the high number is 3 or 11, the called low number has two units: it nets $27; the other low number nets $11; either 2 or 12 nets $26.

Whirl or World bet key

A Whirl/World is five equal units: a four-unit Horn plus one unit on Any 7. Under a standard 4-to-1 Any 7 payout:

Result	Net key	$15 example
7	Push: Any 7 profit offsets four losing Horn units	$0
3 or 11	11 × one unit	$33
2 or 12	26 × one unit	$78

For a $15 Whirl, one unit is $3. That produces 11 × $3 = $33 on 3/11 and 26 × $3 = $78 on 2/12.

Three-Way Craps key

Three-Way Craps splits equally among 2, 3, and 12.

Result	Net per unit	Key on total bet	$12 example
2 or 12	30 − 2 = 28 units	9 × bet + one unit	$112
3	15 − 2 = 13 units	4 × bet + one unit	$52

Three-Way 7 key

At a table that books a Three-Way 7 as three equal hop wagers—1–6, 2–5, and 3–4—each component covers both dice orders and commonly pays 15 to 1. Confirm that definition and paytable before using the key; grouped-hop names and payouts are house-dependent.

Let the total bet be B and each component be u = B/3. Any 7 wins 15u on one component while the other two units lose, so the net is 13u:

net profit = 13 × one-third of the total bet = 4 × total bet + one-third of the total bet

Total Three-Way 7	Each component	Calculation	Net profit on any 7
$3	$1	$15 winner − $2 losers	$13
$75	$25	$375 winner − $50 losers	$325
$138	$46	$690 winner − $92 losers	$598

Under that 15-to-1 paytable, the grouped bet covers all six ways to roll 7 but still has an 11.11% house edge: it wins one roll in six and loses five rolls in six. The shortcut speeds a payoff; it does not improve the bet.

Breakage and improper units

A Horn amount not divisible by four and a Horn High amount not divisible by five create fractional components. Some casinos reject the wager, some round or book it under a posted procedure, and some require the player to add a chip. The clean dealer response is to follow the house procedure—not improvise from a generic internet key.

The original article listed historical breakage shortcuts. They are not presented as universal payouts here because losing $0.75 to rounding, paying it, or refusing the bet are materially different rules. Ask the floor how the house treats breakage.

Dealer learning order

1. Memorize the actual straight-up paytable.
2. Understand wager units and which components lose.
3. Learn hand positioning, game protection, booking, and communication.
4. Use a key only after you can reconstruct the payoff from first principles.
5. Verify unusual amounts against the house procedure.

Keys improve speed; they do not replace procedural accuracy. Players can use the same arithmetic to check a payout, but should not interrupt settlement unless the amount is genuinely wrong.

For wager maximums, see Craps Table Limits. For the standard paytable and house edges, use the Craps Payout Table.

Primary rules source

• Massachusetts Gaming Commission: standard craps wager definitions and payouts