Tournament Variance Calculator

Understanding poker variance is critical for anyone who plays tournaments or sit and goes. Winning players can experience long downswings simply because payouts are top heavy and the field sizes are large. A variance calculator allows you to model those swings, estimate your expected return, and plan a bankroll that keeps you in action during rough patches.

This guide walks beginners through the Poker Tournament Variance tool. We’ll cover what variance and ROI mean, explain each part of the interface, and show you how to interpret the graphs and tables. The guide uses the same assumptions as Primedope’s popular calculator (buy-ins include rake; ROI is applied to the pre-rake amount; payouts are based on the number of players and places paid).

1 Understanding the Math

Before using the calculator, let’s clarify the key statistics it reports. These concepts come from basic probability theory.

2 First Look: The Interface

Open the calculator at your preferred URL. You’ll see a sleek dashboard with lavender tones. At the top is the Tournament Schedule card, followed by space for your results and graphs.

• Sample Size – number of simulation runs. Higher values produce smoother histograms and more reliable confidence intervals but take longer to compute. A few thousand is usually adequate.
• Chart Paths – number of paths shown on the sample paths chart. The charts are representative: the tool internally simulates thousands of runs but displays only a subset.
• Add Tournament Type – open a form to create a new tournament or SNG type.
• Upload CSV – bulk import a schedule from a spreadsheet (more on this later).
• Preset Series – load pre-defined schedules, such as WCOOP/WSOP.

Below these controls you’ll see the Simulate Mixed Schedule button (inactive until you add at least one event) and a summary of total events, total volume and average buy-in.

3 Creating Your First Tournament

4 Building a Mixed Schedule

Most players grind a mix of tournaments. After creating Tournament 1, click Add Tournament Type again to add another. Each card can have different buy-ins, rakes, ROI assumptions, field sizes and number of events. The simulator treats each card independently but runs them sequentially within each path.

You can simulate the schedule in chronological order (as you entered them) or, via an advanced toggle, shuffle them randomly to model a uniform mix. Shuffling spreads big buy-in events throughout the schedule, leading to smoother sample paths.

5 Importing Schedules via CSV

Uploading a CSV is the fastest way to import a large schedule. The CSV must have the following header:

Each row should provide:

• name – descriptive label for the tournament.
• nPlayers – number of entries (not seats; count re-entries separately if you buy-in again). For live events the GTD prize pool divided by the buy-in is a reasonable estimate.
• placesPaid – number of payouts (usually ≈ 15% of the field). The tool doesn’t enforce a sum check here.
• buyIn – the total buy-in amount (e.g. 109 not $109).
• rakePct, roiPct – rake and ROI as percentages (no % sign).
• nEvents – number of times you plan to play the event (often 1).

CSV uploads are helpful for series like WSOP or SCOOP. Populate the sheet with each event’s name, field size and places paid. After upload, each event appears as a separate card with payout structures hidden (unless you expand them) and editable rake/ROI fields. You can delete the events you don’t plan to play or adjust ROI individually.

6 Using Preset Series (WCOOP/WSOP/SCOOP)

The Preset Series dropdown next to Upload CSV lets you load a pre-encoded schedule. When you select WCOOP Series, WSOP Series or SCOOP Series, the app populates all events with default rake and ROI values. In this mode:

• Only rakePct and roiPct are editable. The number of players, places paid and buy-ins come from the organiser’s published schedule.
• There’s an option to set a universal ROI at the top of the list if you want the same edge across all events, and you can override ROI for individual events on their rows.
• Payout structures are precalculated using a balanced 18% paid structure and are hidden to keep the list compact.

You can deselect events (click the trash icon) to exclude them from the schedule.

7 Running the Simulation

Once your schedule is ready, the Simulate Mixed Schedule button becomes active and displays the total number of events. Click it to start the simulation. During computation the button shows a loading spinner. After a short delay (longer for large schedules and high sample sizes) the results section appears:

Distribution for All Tournaments

A histogram of final profits across all simulated runs. The x-axis shows profit ranges; the y-axis shows frequency. A positively skewed distribution indicates many modest wins and a few very large scores.

20 Representative Sample Paths

This chart shows 20 individual cumulative profit paths drawn from the simulation. The tool selects a spread of quantiles: the worst run, best run, median and other evenly spaced samples. Lines representing the mean and median cross the middle, while shaded areas indicate the 5th–95th percentile band (default) or 1st–99th if you change the band. A steep green line indicates a big score; the red line (worst run) shows the longest downswing.

Summary Statistics Card

• Expected Value – the simulated total profit across the schedule. For realistic ROI values, this should be close to ROI × total buy-ins.
• Standard Deviation – the simulation-based SD of total profit. Higher SD implies bigger swings.
• Probability of finishing below $0 (with bankroll) – percentage of runs that ended with a loss after all events including your starting bankroll.
• Bankroll (5% RoR) – computed via risk of ruin simulation. It tells you the starting roll required so that only 5% of runs go broke at any point in the schedule.

Variance in Numbers Table

This table compares the mathematical calculations to the simulated results:

• Tournament types – number of distinct cards in your schedule.
• Total number of tournaments – sum of all events across cards.
• Sample size – number of simulations performed.
• Sum buy-ins – total amount invested (excluding rake).
• EV (mathematically) – ROI × sum buy-ins.
• EV (simulated) – mean of all final profits.
• ROI (mathematically) and ROI (simulated) – your expected and simulated ROI across the schedule.
• SD (mathematically) – theoretical standard deviation computed from the payout distributions.
• SD (simulated) – standard deviation measured from the simulations.

Confidence Intervals Table

For each confidence level (70%, 95%, 99.7%), the table shows the confidence interval for total profit and ROI interval. These ranges tell you where your results will likely fall relative to your investment. Negative lower bounds are normal when variance is high.

Bankroll & Risk of Ruin Table

This table provides the minimum bankroll to achieve a given risk of ruin threshold. For instance, a 50% RoR bankroll means half of the simulated runs went broke; a 1% RoR bankroll means only 1% did. The bottom line in this section shows how many simulated runs never dipped below zero with your stated bankroll.

9 Final Thoughts

The Poker Tournament Variance Calculator is a versatile tool for tournament players. You can build schedules combining SNGs, daily MTTs and massive series events; import CSVs; load preset WSOP, WCOOP or SCOOP schedules; tweak rake and ROI assumptions; and visualise your risk through simulations.

To make the most of it:

1. Know your numbers. Estimate your ROI realistically, and use actual field sizes and payouts when possible.
2. Plan your bankroll. Use the risk of ruin table to choose a starting roll you’re comfortable with, remembering that bigger events require bigger cushions.
3. Interpret variance wisely. Even winning players endure downswings. Confidence intervals and sample paths help set expectations and reduce emotional swings.
4. Iterate and adjust. After you play a few hundred events, update your ROI assumptions and rerun the simulation. Variance is a long game—continual analysis helps you stay ahead.