Variance Calculator

Tournament math

Simulate your results over any sample size — confidence intervals, downswing depth and duration, and the bankroll it takes to survive them at your stakes.

20 samples & confidence intervals

Winnings in BB over 100k hands. Best and worst run out of 1,000 trials.

Expected value 70% 95% Best / worst

Expected winnings 3,000 BB $3,000 at NL100 over 100k hands

Standard deviation ± 2.85 BB/100 ± 2,846 BB across the full 100k hands

7 lives in 10 land between

Worst 50 BB 0.05 BB/100

Best 5,950 BB 5.95 BB/100

the middle 70% of outcomes over 100k hands

19 lives in 20 land between

Worst -2,578 BB -2.58 BB/100

Best 8,578 BB 8.58 BB/100

the middle 95% — the rare 1 in 20 falls outside

Chance of being down 14.6% after the full 100k hands, at this win rate

Bankroll for <5% ruin 40 buy-ins 4,044 BB · $4,044 at NL100

One life, with its downswings

A single run over 870k hands. Winnings above, distance below the previous peak below.

Sample size 870k

Deepest downswing this run: — Longest stretch under a peak: — Finished at: —

How deep, how often

Share of hands spent inside a downswing of at least this size, over a 20M-hand life.

Downswing	Time spent

How long, how often

A downswing is not over until you take back the old peak.

Duration	Time spent

Bankroll requirements

From the same win rate and standard deviation. Assumes you move down when the roll shrinks.

Required at 5% risk of ruin 40 buy-ins 4,044 BB · $4,044 at NL100

If your win rate is wrong

True win rate	Buy-ins	Bankroll
3.00 BB/100 (your estimate)	40	$4,044
1.98 BB/100	61	$6,128
1.50 BB/100	81	$8,088
0.99 BB/100	123	$12,255

Every risk tier

Risk of ruin	Style	Buy-ins	Bankroll
1%	Very conservative	62	$6,217
2%	Conservative	53	$5,281
5%	Standard	40	$4,044
10%	Aggressive	31	$3,108

By stake, at 5% risk

Stake	Buy-in	Bankroll
NL2	$2	$80.88
NL5	$5	$202
NL10	$10	$404
NL25	$25	$1,011
NL50	$50	$2,022
NL100	$100	$4,044
NL200	$200	$8,088
NL500	$500	$20,221
NL1000	$1,000	$40,442
NL2000	$2,000	$80,885
NL5000	$5,000	$202,212

Read the bands, not the lines

Every grey line is a possible you at the same skill. The bands say where 70% and 95% of those lives land — identical win rates, wildly different results.

Rake is inside the win rate

These numbers assume the win rate you typed is after rake. A 5 BB/100 winner paying 6 BB/100 in rake is a losing player with a very optimistic chart.

Downswings underestimate

The tables sample a 20M-hand life at 100-hand resolution, so short sharp dips get smoothed away. Treat them as a floor, not a ceiling.