Blackjack Expected-Loss Calculator

By Originally published

Estimate the long-run mathematical cost of a blackjack session from your average initial bet, pace of play, session length and estimated house edge. The result is an average over extensive play—not a prediction of what will happen today.

Transparent session math

Estimate expected loss

Amounts are shown in currency units. The mathematics is currency-neutral.


Use the average initial wager, before doubles and splits.


Live tables are usually slower than automated games.


Decimals are accepted—for example, 1.5 hours.


Enter 0.5 for 0.50%, not 0.005.


These are teaching estimates, not universal game values. The 6:5 preset adds the sourced approximate 1.39-percentage-point payout effect to a 0.50% baseline.

Estimated long-run average

Session results

Estimated hands160
Total amount wagered4,000.00 units
Expected loss per hour10.00 units
Expected loss for session20.00 units
Expected loss per 100 hands12.50 units

This estimate uses initial wagers as the action base. Actual money placed can be higher when you double or split.

If the house edge changes

The comparison below changes the edge by 0.25 percentage points while holding bet size, speed and duration constant.

Lower edge10.00 units0.25% edge · 10.00 fewer units
Entered edge20.00 units0.50% edge
Higher edge30.00 units0.75% edge · 10.00 more units

Session expected loss at several house-edge values
House edge Expected loss Relative size

Approximate 3:2 versus 6:5 effect

With the entered edge treated as the 3:2 baseline, 6:5 is modeled by adding approximately 1.39 percentage points. The exact difference varies slightly with the full rules.

Blackjack payout Modeled edge Session expected loss
3:2 baseline 0.50% 20.00 units
6:5 approximation 1.89% 75.60 units
Approximate added expected loss +1.39 points 55.60 units

JavaScript is unavailable. You can still use the formulas below. For the default example—25 units, 80 hands per hour, 2 hours and a 0.50% edge—the estimate is 160 hands, 4,000 units wagered, 10 units lost per hour on average and 20 units for the session.

Formula and methodology

Total hands = hands per hour × hours

Total wagered = average bet × total hands

Expected session loss = total wagered × house edge

Expected loss per hour = average bet × hands per hour × house edge

The calculator converts the percentage to a decimal before multiplying. A 0.50% house edge is 0.005. Results retain full precision internally and are rounded only for display.

Worked example

Suppose the average initial bet is 25 units, play averages 80 hands per hour, the session lasts 2 hours and the estimated house edge is 0.50%.

  • Total hands: 80 × 2 = 160
  • Total wagered: 25 × 160 = 4,000 units
  • Expected loss per hour: 25 × 80 × 0.005 = 10 units
  • Expected session loss: 4,000 × 0.005 = 20 units
  • Expected loss per 100 hands: 25 × 100 × 0.005 = 12.50 units

Assumptions and limitations

  • The average bet is treated as the initial wager per hand. Doubles, splits, insurance and side bets can increase money actually placed.
  • The entered house edge must match the game’s complete rules and the player’s strategy. A low published edge normally assumes accurate basic strategy.
  • Hands per hour is an estimate. Table occupancy, dealer speed, online automation and breaks change actual pace.
  • Expected loss is linear in bet size, hands and edge. Variance is not: short-session results can depart widely from expectation.
  • The 6:5 comparison isolates an approximate payout effect. It is not a full rules engine.

Why one session can look completely different

Expected loss is the center of a long-run distribution, not a promise that every session will lose that amount. Naturals, doubles, splits, pushes and ordinary streaks produce substantial variance. Winning in one session does not disprove a house edge; losing more than the estimate does not mean the formula failed.

Sources