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Bankroll Truth

The arithmetic of a blackjack game: what an edge is worth per hour, how wide the swings around it run, how much bankroll survives them, and how long before any of it means anything. Set your game, read your numbers.

Software like this sells for $125 to $250. Bankroll Truth is free.

Our rule here: give more than you take. Unless you're taking from the casino.

Full precision, the same figures for everyone, and the arithmetic is published — the methods note shows the simulation and the closed-form calculation checking each other.

Free, like the drill and the trainers.

This is mathematics, not a forecast. It describes the shape of a game — expectation, variance, and risk — under the assumptions you set. It does not predict your results, and no calculator can. Conditions at a real table vary, and every number here moves when the assumptions do.

Pick the game you actually play. Get the four numbers that matter.

The game you play
Expected per hour
$0.83
edge 0.03% of action
Swing per hour (1 SD)
$438
526× the hourly average
Risk of ruin
91.7%
400u bankroll, played indefinitely
Hands until it means anything
27,682,844
276,828 hours
Bankroll for 5% ruin
$344,832
13,793u
Bankroll for 1% ruin
$530,090
21,204u
Certainty equivalent
-$874
over 100 hours · EV $83
Reach target before broke
52.2%
target $10,000

A thousand versions of your next 100 hours

measured

Each faint line is one possible run of this exact game. The bands hold the middle half and the middle ninety percent of them. The cone is the point: the average is a line, but nobody plays the average.

broke765u-57u400u100 hours

The bet ramp this bankroll can carry

Generated from the measured edge at each true count and your risk tolerance — not copied from a chart. Spread 1 to 7 units · playing every hand.

True countBetEdgeShare of rounds
−3 and below1u-3.13%8.8%
-21u-2.29%6.8%
-11u-1.56%12.3%
01u-0.63%45.3%
+11u0.19%11.8%
+22u1.18%6.5%
+32u1.08%3.7%
+42u1.63%2.1%
+54u2.49%1.2%
+6 and up7u5.11%1.4%

The chart, re-derived for your table

Basic strategy is not a tradition and it is not a document. It is the answer to an arithmetic problem, and the answer changes when the rules change. So this does not show you a chart — it works one out for the rules you set, by pricing every option and taking the best one.

Computed for these exact rules — not looked up. Cells outlined faintly are close calls, where the two best options are worth almost the same and published charts often disagree with each other.

Hard totals

2345678910A
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

Soft totals

2345678910A
A,2
A,3
A,4
A,5
A,6
A,7
A,8
A,9

Pairs

2345678910A
2,2
3,3
4,4
5,5
6,6
7,7
8,8
9,9
T,T
A,A
hitstanddoublesplitsurrender

This is a correctness claim, not an advantage claim. A chart derived for your exact table is right rather than approximately right; it does not beat the house on its own, and nothing here should be read as saying it does. The improvement that actually moves the number is the count.

Trip planner

Hands
1,500
Expected
$12
Likely range
-$3,377 — $3,402
19 trips in 20 land inside this

Game comparator

Pick a second game to hold beside this one.

Every assumption behind these numbers

Nothing here is buried in a settings screen. Change any of it and every number above re-flows immediately.

Decks
6
Dealer on soft 17
hits
Blackjack pays
3:2
Double after split
yes
Late surrender
no
Resplit aces
no
Penetration
75%
Hands per hour dealt
100
Hands per hour played
100
Unit
$25
Bankroll
$10,000 · 400u
Bet sizing
50% Kelly, capped at 12u
Counting system
Hi-Lo, running count over decks remaining
Session length
4 hours

True count is running count divided by decks remaining, estimated from the discard tray the way a player actually estimates it.

Playing decisions come from the same strategy engine the drills and the graded test use — basic strategy for a basic player, plus the index deviations and the insurance rule for a counting player.

Send this setup to someone

Every dial above travels in the link. They open it and see exactly what you see.

Your sessions against this curve

Members who log sessions can lay their real results over the expected line and its bands, and see whether a bad month is variance or a leak. The tracker answers what happened; this answers whether it was normal.

The calculator above is complete and free. This overlay needs your logged sessions, which is the only reason it sits behind an account.

Members only

How this works, and how to check it

Two independent layers compute every number on this page, and they are built to disagree if either one is wrong.

The CLOSED-FORM layer is standard applied probability. A bankroll is treated as a random walk, which over many rounds behaves like Brownian motion with drift — and that approximation is what makes exact formulas possible. Expected value is linear in the number of rounds; standard deviation grows with the square root of it; risk of ruin follows from the classical barrier problems that have been in the literature for a century; optimal bet sizing follows Kelly's growth criterion. None of this is proprietary to anyone, and every formula is derived in the comments of the source rather than asserted.

The SIMULATION layer plays actual hands. It deals seeded shoes and plays them with the same strategy engine the drills and the graded test use — the same basic strategy, the same index deviations, the same insurance rule. Nothing is imported from anyone else's software, and no reference table was copied from any source: every figure this page shows was produced by playing the hands here.

The two layers are cross-checked against each other. The simulation measures the edge and the spread of outcomes; the closed form predicts what the risk of ruin should be given those measurements; and the simulation is then run again as thousands of independent bankroll paths to see how often ruin actually happens. Where the two agree, you can trust either. Where they disagree, the simulation is the more honest one, because it made fewer assumptions — and the disagreement is reported rather than smoothed away.

The approximation is weakest over short horizons and with bets that are large relative to the bankroll. That is exactly where a session-length answer matters most, so treat short-run numbers as the roughest thing on the page.

Practise the count itself in the free drillRead the bankroll guideWhat is the Kelly criterion?What each of these numbers means, in longer form

The course works through bankroll and bet sizing in its own module, with the founder's corrections published inside it.

These figures describe a mathematical model of a game, computed from the assumptions you entered. They are not a prediction of your results, not financial advice, and not a claim about what anyone earns. Gambling involves risk and most people who gamble lose money. If it stops being a choice, the National Problem Gambling Helpline is 1-800-522-4700.