Poker variance refers to the natural fluctuations in a player’s results due to luck and probability, causing short-term deviations from expected long-term outcomes. An explanation of how the calculator works can be found below.
1. Set Your Parameters
2. Run the Variance Simulation
3. Analyze the Risk of Ruin
4. Adjust Bankroll Management
Playing MTTs? Use our Tournament Variance Calculator
20 samples and confidence intervals
Variance in numbers
Detailed sample with downswings
Downswings in numbers
How to Use the Poker Variance Calculator
This section explains what the calculator does, what the numbers mean, and how to use the results to make better bankroll and game selection decisions.
Step 1: Enter Your Data
Enter your win rate (in BB/100), standard deviation (in BB/100), and the number of hands you want to simulate. Both stats can be pulled directly from PokerTracker or Hold’em Manager.
The observed win rate field is optional. If you enter it, the calculator will tell you the probability of running at or above that rate over the sample — useful for answering the question “is my current win rate real, or am I running hot?”
Hit Calculate and the simulator runs the numbers.
Step 2: Read the Sample Chart
The first chart runs 20 random samples using your inputs. The straight black line is your expected value (EV) — what you’d earn if results perfectly matched your win rate over time. The light and dark green curves are the 70% and 95% confidence intervals. At any point along the x-axis, there’s a 70% chance your actual results fall within the inner band, and a 95% chance they fall within the outer band.
This is the chart that makes variance visible. Two players with identical win rates and standard deviations can end up with wildly different results over the same number of hands. That’s not skill — it’s math.
Step 3: Understand the Numbers
Below the chart, the calculator outputs a detailed breakdown:
- Expected winnings — estimated profit over the simulated hands at your win rate
- Standard deviation after X hands — how much your actual results will differ from EV on average. Shown in absolute BB and as a BB/100 impact on your measured win rate.
- 70% / 95% confidence intervals — the range your results will land in 70% and 95% of the time. The BB/100 version shows how wide your true win rate confidence interval is — often much wider than players expect.
- Probability of loss after X hands — the chance you’ll be in the red after the full sample, even with a positive win rate.
- Observed win rate probability — if you entered an observed rate, this shows how likely you are to run at or above it. A useful reality check when you suspect you’re on the good side of variance.
- Minimum bankroll for less than 5% risk of ruin — the bankroll size that gives you a 95% chance of never going broke. This is the number that matters most for bankroll management.
One thing the calculator can’t account for is rake. Your true win rate — the one that matters for these simulations — is your win rate after rake. A player winning 5 BB/100 before rake at a site taking 8 BB/100 in effective rake is actually a losing player. If you haven’t already, it’s worth checking how your site compares: Rake Comparison Calculator →
Step 4: Explore the Downswing Chart
This chart simulates a single run over 100,000 to 10 million hands (use the slider to adjust). The blue line tracks cumulative winnings on the right axis. The red area is the downswing tracker — at every point, it shows how far below the previous peak the sample currently sits, with its scale on the left axis.
In the example above, the simulated player finished with over 25,000 BB in profit after 2.5 million hands — but endured a downswing of nearly 10,000 BB between hand 1.2 million and hand 2 million. That’s roughly 800,000 hands stuck below a previous high. This is normal variance for a winning player.
Step 5: Check the Downswing Tables
The final section simulates 100 million hands and tracks every downswing. Two tables summarize the results:
The first table shows downswing depth — how often you’ll be stuck in a downswing of at least X big blinds. For example, “1000+ BB – 31.77%” means you’ll be in the middle of a 1,000+ BB downswing roughly a third of the time.
The second table shows downswing duration — how long downswings last. For example, “50000+ Hands – 15.81%” means you’ll be in a 50,000+ hand downswing about 16% of the time. A downswing isn’t considered over until you’ve fully recovered to the previous peak.
These numbers tend to underestimate real downswings, but they give you a realistic picture of what to expect. The takeaway: downswings aren’t a question of if but when and how deep.
How Many Buyins Do I Need? Using the Calculator for Bankroll Management
The variance calculator doubles as a poker bankroll calculator. The “Minimum bankroll for less than 5% risk of ruin” output tells you exactly how much you need to have behind you to survive the swings at your stakes.
Here’s how the math works in practice. A solid NLH 6-max player with a 3 BB/100 win rate and 90 BB/100 standard deviation needs roughly 67 buyins (6,700 BB) to keep their risk of ruin below 5%. That means at $1/$2, you need around $13,400. At $0.50/$1, around $6,700.
Raise the standard deviation to 110 BB/100 — common for aggressive players or PLO — and the required bankroll jumps to over 100 buyins. Drop the win rate to 1.5 BB/100 and you’re looking at 200+ buyins to stay safe.
The relationship is straightforward: higher variance and lower win rates demand bigger bankrolls. This is why game selection and rake matter so much — they directly affect your effective win rate, which is the single biggest lever on how much bankroll you need.
A few rules of thumb based on running thousands of simulations:
- NLH 6-max, solid winner (3+ BB/100): 50–75 buyins
- NLH 6-max, small winner (1–2 BB/100): 100–200 buyins
- PLO 6-max, solid winner (3+ BB/100): 80–120 buyins
- NLH full ring, solid winner (3+ BB/100): 30–50 buyins
These are guidelines, not guarantees. Run the calculator with your actual numbers. Your win rate and standard deviation are specific to your play style, stakes, and the sites you play on. Generic bankroll advice can’t account for that — this tool can.
If the required bankroll feels uncomfortably large, the most effective fix isn’t to gamble with a shorter stack — it’s to increase your effective win rate. That means either improving your game or reducing the rake you pay. Often, the simplest move is switching to a lower-rake site.
Why Rake Matters More Than You Think
Rake is the silent killer of win rates, and most players drastically underestimate its impact on variance and bankroll requirements.
Consider two identical players with a 5 BB/100 win rate before rake. Player A plays on a site taking 8 BB/100 in effective rake (net win rate: −3 BB/100 — a losing player). Player B plays on a site taking 4 BB/100 in effective rake (net win rate: 1 BB/100 — a modest winner). Same skill, completely different outcomes.
The effect on bankroll requirements is dramatic. A player with a 3 BB/100 net win rate and 90 BB/100 standard deviation needs about 67 buyins. Drop that win rate to 1.5 BB/100 by playing on a higher-rake site and the required bankroll roughly doubles. Rake doesn’t just cost you money per hand — it compounds into longer downswings, bigger bankroll requirements, and a higher probability of going broke.
This is why we built the Rake Comparison Calculator — so you can see exactly what each site costs you at your stakes, using real hand data rather than theoretical rake structures.
For players looking to minimize rake: we have tested every major poker room dating back to 2008. In 2026, CoinPoker consistently has the lowest effective rake across most stakes, combined with 33% flat rakeback and a 150% deposit bonus up to $2,000. For US players, Ignition and Bovada offer anonymous tables with competitive rake structures.
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About This Calculator
The Primedope Poker Variance Calculator was built by Arved Klöhn and first published in August 2013. Arved is a mathematician and poker player whose passion for both fields led him to create what has become the industry-standard variance tool. He has continuously maintained and improved the calculator over the past 13 years.
The site’s poker room reviews, rake analysis, and strategy content are managed by Zach Schneider, a professional poker player and industry insider for over 20 years. Zach has managed staking operations for 150+ tournament professionals and brings real-world bankroll management experience to the content and recommendations on this page.
Primedope’s tools are referenced by Wikipedia, PokerNews, GTO Wizard, and poker training sites worldwide. The variance calculator is used daily by professional players, staking operations, and coaches to make informed bankroll and game selection decisions.
The math behind the calculator uses Monte Carlo simulation — the same method used in quantitative finance and risk analysis. It runs thousands of randomized samples using your inputs to model the full distribution of possible outcomes, confidence intervals, and downswing probabilities. This isn’t a simplified formula or approximation — it’s a full statistical simulation.
Have questions, found a bug, or want to suggest improvements? Email info@primedope.com or leave a comment below.
What to Do Next
Now that you understand what variance looks like over your sample size, here are the logical next steps:
Check your effective win rate. Rake eats into your bottom line more than most players realize. Use the Rake Comparison Calculator to see how your current site stacks up — and whether switching could meaningfully improve your results.
Run the numbers for tournaments. MTT variance is a different beast entirely. If you play tournaments, the Tournament Variance Calculator will show you just how brutal the swings can get (and how much bankroll you actually need).
Understand ICM pressure. If you’re a tournament player making deal decisions or playing final tables, ICM changes everything. The ICM Calculator and our ICM explainer can help.
See variance in action. For real-world examples of how variance plays out in actual cash game sessions, check out Examples and Impacts of Variance in Cash Games.
Find softer games. As an industry insider (professional player, backer, training site expert) for 20 years, the most important thing about poker is game selection. We have tested countless poker rooms dating back to 2008 and in 2026 we recommend CoinPoker for its soft low-stakes games, industry low rake, and generous player rewards. For US players or those looking for anonymous tables, Ignition and Bovada remain solid alternatives.
Frequently Asked Questions
What is a good standard deviation in poker?
For NLH 6-max, a standard deviation between 75 and 120 BB/100 is typical. Tighter players tend toward the lower end; aggressive, multi-tabling players trend higher. PLO players will see 100–160 BB/100. You can find your exact standard deviation in PokerTracker or Hold’em Manager under your session stats.
How many hands do I need to know my true win rate?
More than most players think. At a typical standard deviation of 90 BB/100, you need roughly 100,000 hands for a 95% confidence interval of ±1.8 BB/100 around your measured win rate. That means a player showing 4 BB/100 over 100k hands could realistically be anywhere from 2.2 to 5.8 BB/100. For a tighter estimate, you need 500,000+ hands. The calculator’s confidence interval output shows this for your specific numbers.
How many buyins do I need for online poker?
It depends on your win rate, standard deviation, and risk tolerance. As a rough guide: 50–75 buyins for a solid NLH 6-max winner, 100–200 for a smaller winner, and 80–120 for PLO. Enter your actual stats into the calculator and check the “Minimum bankroll for less than 5% risk of ruin” output for a precise answer tailored to your game.
What is risk of ruin in poker?
Risk of ruin is the probability that you will lose your entire bankroll before your long-term edge compounds enough to sustain you. The calculator computes this using your win rate and standard deviation. A 5% risk of ruin means that 1 in 20 players with your exact stats and bankroll will eventually go broke — even though they’re long-term winners.
Does rake affect variance?
Rake doesn’t affect your standard deviation directly, but it reduces your effective win rate — which has a massive impact on bankroll requirements and downswing severity. A lower effective win rate means longer downswings, higher risk of ruin, and more buyins needed to stay solvent. Use the Rake Comparison Calculator to see how much rake actually costs you at your stakes.
Is this calculator accurate for PLO?
Yes. The calculator works for any cash game format — NLH, PLO, PLO5, or mixed games. The math is format-agnostic; what matters is your win rate and standard deviation, which you enter yourself. PLO players should expect higher standard deviations (100–160 BB/100 for 6-max) and will typically need larger bankrolls as a result.
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