## Risk of Ruin is:

The probability that you will lose your entire bankroll

To calculate the bankroll size you need for an acceptable risk of ruin, you need the following information:

- Net Win per Hand of Blackjack Played
- Standard Deviation per Hand of Blackjack
- Risk of Ruin desired (percent)

## Net Win per Hand is the sum of:

- Loss from playing blackjack
- Amount received from comps = (comps received per hour) / hands per hour / betting unit size

#### Example:

- 2D H17 DAS game loss = -0.0046 units (decimal form of expected value %)
- Comps received = $2 / 53 hands per hour / $5 = .0075 units
- Net win per hand = -.0046 + .0075 = .0029

Every time you receive a comp you need to add to your bankroll the cash value of the comp to replenish your bankroll. Remember you would have spent this money if you didn’t receive comps.

## Standard Deviation per Hand of Blackjack

When playing blackjack and flat betting (not varying your bets between rounds), the standard deviation per hand is approximately 1.1418.

## Blackjack Risk of Ruin

If your total bankroll is $1,000 and you bet $5 per hand then your bankroll size is 200 units ($1,000 / $5). Looking at the chart below your risk of ruin for this scenario is approximately 39.8%.

## Here is another example of calculating risk of ruin based on receiving Free Rooms in Vegas.

- Betting unit size is $25 / hand
- Net Win per Hand is ( $85 in comps / 4 hours of play / 70 hands per hour / $25 betting unit size ) - 0.0060 loss from playing blackjack = 0.0061

**If your bankroll is $5000 (200 units) then your risk of ruin is approximately 15.9%**

**If your bankroll is $7500 (300 units) then your risk of ruin is approximately 6.3%**

It is critical to understand bankroll requirements when playing blackjack so that you understand the risk of losing your entire bankroll and you can size your bankroll appropriately.