Stokastic Sims Pool Size: How Big Should Your Simulated Field Be?

The single most common question I get from members who just opened the late swap tool is some version of this: "Why do the swaps only have 2,000 pool size instead of 5,000?" It feels like a bug, or like you are getting a smaller, weaker version of the tool. You are not. That number is a setting doing exactly what it should, and once you understand what it controls, you stop reaching for the biggest option and start reaching for the right one.

Here is the whole idea in one line: your pool size is the simulated field, so realism beats size every time. A pool that mimics the contest you are actually in will give you sharper lineups than a giant pool that models a contest you never entered. Let me show you why, starting with what that number really means, and finishing with the one time you actually should make it bigger.

What "Pool Size" Actually Means In The Stokastic Sims

Pool size is not how many lineups you get. It is how many opponent lineups the Sims build to fill the tournament you are simulating.

When you run the Contest Sims, the tool constructs a realistic FIELD, thousands of opponent lineups shaped like the contest you are entering, then plays the slate out over and over, grades every one of your builds by simulated ROI against that field, and the tool surfaces the strongest of them. Pool size is the dial that sets how big that opponent field is. So a 2,000 pool is not a limit on you. It is a 2,000-entry room of simulated opponents for your lineups to compete against.

That reframes the whole question. The choice is not "how much tool do I get," it is "how big is the contest I want to model." And the honest answer, most nights, is not 5,000.

Why The Swaps Show 2,000 And Not 5,000

As we covered in office hours when a member asked this exact thing, the swap pools are sized to mimic the contests you are actually playing, not the biggest number the tool can hold. Staff put it plainly: the different pools are set up to be closest to the contests that you see. Late-swap fields tend to run smaller, and NBA is where late swap matters most, so the swap preset is built to represent a realistic field rather than the biggest possible pool.

The realism cuts both ways, and this is the part that relaxes people: your contest does not have to match a preset exactly. A 10,000 pool models a 15,000-entry contest fine, because the field behaves the same way. You are not looking for a perfect match. You are looking for a field that behaves like yours, and the closest preset already does that.

So the swaps show 2,000 because a late-swap contest usually looks like a 2,000-entry room. That is the whole answer to the late swap pool size question: it is not a smaller tool, it is a right-sized one.

Bigger Isn't Better: Match The Pool To Your Contest

Once you accept that pool size equals field size, picking one gets easy. You are not chasing a big number, you are describing your contest to the sim. Here is how I map the pool to what I am actually entering:

Contest I'm Entering	Pool I model it with	Why
Large-Field GPP (Milly Maker, 100K+ Entries)	The biggest preset	A huge, soft, chalky field only shows up in a large pool
Mid-Size GPP (5K To 20K Entries)	The closest 5K to 10K preset	Near enough behaves like yours; exact match is not required
Small High-Stakes GPP (250 To 500 Entries, $55+)	~500	A small sharp field needs a small pool to grade it right
Late Swap (Especially NBA, Smaller Field)	The swap default (~2,000)	Sized to a real late-swap contest, not a weekend monster

The row I keep coming back to is the small high-stakes one. When a member asked what pool to use for a tight high-stakes contest, staff told them to try somewhere between 250 or 500 on the contest size and not to go much bigger than that. That sounds backwards until you remember why. High-stakes fields are the sharp players, and sharp players cluster into a lot of the same chalky, game-theory-correct builds, so they overlap each other in a small room. A 500-entry pool captures that tight, overlapping field. Blow it up to 5,000 and you have invented thousands of opponents who were never in your contest, and your leverage math is now solving for the wrong room.

Pick the pool that looks like your contest, then leave it alone. The reader who takes one thing from this article: size is not quality, fit is. Model the field you are actually in and the simulated ROI you get back means something. If you want to try it on tonight's board, the Stokastic Sims live inside Stokastic+ and code POOLSIZE10 takes 10% off your first Data + Sims or Sims MAX payment: size your first slate.

The Real Cost Of Going Too Big (Or Too Small)

Bigger pools are not free. They generate more opponent lineups and take longer to run, and the payoff is only real if your contest is actually that big. Model a 500-entry high-stakes contest with a 20,000 pool and you have paid the time cost for a field that does not resemble yours, which is the worst of both worlds: slower AND less accurate.

Too small has a cost too, and it is the flip side of that high-stakes note above. If you shrink the pool below the contest you are in, the sim has too few opponents to grade a stable ranking, and your ROI numbers get noisy. That is exactly why staff nudged the high-stakes member toward 500 rather than 250: enough entries to grade the field cleanly, without inflating it past the real contest. The target is not "small" or "big." It is "the size of your actual contest."

Change The Pool Size, Re-Run Everything

Here is the rule that trips people up most. Pool size is not a cosmetic slider you can nudge at the end. It is a generation input, so the moment you change it, everything downstream has to be rebuilt.

The clean way to think about it, straight from how staff coach it: if you change the contest pool size, you definitely need to go through and re-run, because the entire field regenerated. Your ROI ranks, your leverage, your best builds, all of it was graded against the old field and no longer applies until you re-run. Contrast that with the light-touch levers, ROI boosts, exposure caps, filtering to five-man stacks. Those you apply at the end, once you are close to final, with no full re-run. Pool size is the opposite kind of setting. Set it FIRST, regenerate, and only then start tuning the dials that do not require a rebuild.

That is the callback to the very first section: the pool is the field, and if you rebuild the field, you rebuild the grades.

Rule of thumb: pool size and projection changes force a full re-run; ROI boosts, exposure caps, and stack filters do not. Set the field first, then tune the light dials last.

How Pool Size Talks To Your Other Settings

Pool size does not sit alone. It sets the room, and a couple of other settings only make sense once the room is right.

• Contest Archetype tells the field what KIND of opponents fill that room, low stakes for the soft chalky mini-maxes, high stakes for the sharp $55+ fields. Pool size sets how many; archetype sets how sharp. You want both matched to the same real contest.
• Uniques depends partly on pool size and slate size, so it is a decision you make after the field is set, not before. The tool answers it for you at the bottom of the board, where it shows the min and average ROI at each uniques setting for tonight's slate.

If the underlying workflow is still new, the Stokastic MLB Sims walk-through covers the full build order, and the NBA Sims guide does the same for the sport where late swap swings hardest. Because your DFS contest pool size should track the contests worth playing, our DFS contest selection guide pairs naturally with this one.

A Worked Example: Sizing A $55 High-Stakes NBA Slate

Let me put all of it on one contest. Say I am late-swapping a 300-entry, $55 high-stakes NBA GPP. Here is the exact sequence I run, and why each step falls where it does:

1. I check the default before I touch it. The swap preset sits near 2,000, which models a normal late-swap field. My contest is a 300-entry high-stakes room, smaller and sharper than that, so 2,000 is actually too big for this one.
2. I drop the pool to 500. That is the top of staff's 250-to-500 high-stakes range, and it gives the sim enough opponents to grade a stable ranking without inventing thousands who were never in my 300-person contest.
3. I set the archetype to High Stakes. Now those 500 simulated opponents build like sharp players, not the soft chalk of a mini-max, so the field matches the contest on both size and sharpness.
4. I regenerate, then read the board. Because I changed the pool size, every ROI rank rebuilt against the new 500-entry field. This is the re-run rule in action, and skipping it would leave me reading grades from the old 2,000 field.
5. I set uniques last. The tool lays out the ROI trade-off for each uniques count on tonight's slate at the bottom of the board, and I pick from that data instead of guessing.

The whole move took under a minute, and the simulated ROI I am now reading describes a 500-entry sharp field that actually looks like my contest. Leave it at 2,000, or crank it to 5,000, and I would be optimizing for a room I never entered. That is the difference between a number that means something and a number that just looks big.

The Bottom Line

Pool size looks like a "how much do I get" setting and it is really a "what am I modeling" setting. The swaps show 2,000 because a late-swap contest looks like a 2,000-entry room, not because you were handed a lesser tool. Match the pool to the contest you are actually in, go bigger only when your contest genuinely is, re-run the moment you change it, and read the simulated ROI knowing it now describes a field that looks like yours. Get that fit right and every dial after it, archetype, uniques, exposure, is solving the correct problem. Fit is the edge. Size was never the point.

Size Your Field On A Live Slate

The Stokastic Sims build a realistic opponent field, simulate your lineups against it over and over, and the tool surfaces the builds with the best simulated ROI, with the pool-size, archetype, and uniques controls covered above. They live inside Stokastic+, and code POOLSIZE10 takes 10% off your first Data + Sims or Sims MAX payment: set your pool on today's board with 10% off. New to the Sims? Start free with the DFS Sims and pull a live slate from the MLB DataHub.

Frequently Asked Questions

Why do the swaps only show 2,000 pool size instead of 5,000? Because the swap pool is sized to mimic a real late-swap contest, which is usually a smaller, sharper field than a weekend milly maker. It is not a smaller tool, it is a right-sized field. Your contest does not need to match the preset exactly, the closest one already behaves like yours.

Why is a bigger pool not always better? Because the pool is the simulated field, and a field bigger than your real contest invents opponents who were never in it. That distorts the leverage math and slows the run for no benefit. Bigger only helps when your actual contest is actually that big.

What pool size should I use for a small high-stakes contest? Around 500. Staff steer high-stakes players to roughly 250 to 500 and warn against going much bigger, because a sharp, tightly clustered high-stakes field is modeled best in a small room with enough entries to grade a stable ranking.

Do I have to re-run the sim after changing the pool size? Yes. Pool size is a generation input, so changing it regenerates the entire field and every ROI rank with it. Re-run after any pool-size change. Light adjustments like ROI boosts and exposure caps are the ones you can apply at the end without a full rebuild.

Does the pool size have to match my contest exactly? No. You are looking for a field that behaves like yours, not a perfect number. A 10,000 pool models a 15,000-entry contest fine, because the two fields behave the same way. Pick the closest preset and move on.