NFL DFS Contest Simulator: How To Use The Stokastic Pre-Contest Sims Tool

Projections tell you how many points a player should score. They do not tell you which of your lineups actually wins money on Sunday. That gap is the entire job of the NFL DFS contest simulator: you feed it the pool of lineups you built, it runs that pool against itself across tens of thousands of simulated contests, and it ranks every build by how it finishes when your lineups play each other for real. This walkthrough is a hands-on tour of the Stokastic pre-contest sims tool, one tab at a time, and it centers on the single setting most people never touch, the one that changes which lineups you should actually enter.

In Summary

• The Stokastic pre-contest simulator takes the lineups you built (up to 10,000 with the top package), plays them against each other across tens of thousands of simulated contests, and sorts them by simulated ROI, the cleanest signal of which builds win money.
• Match the percent-to-first setting to your contest's payout structure before you trust the sort. A flat double-up and a top-heavy Milly Maker reward completely different lineups.
• Read the output tabs in order: the main lineup grid, then Player ROI, Stack ROI, and Exposures with leverage, to see who is carrying your builds and who is sinking them.
• Shape exposures without rebuilding from scratch: a per-player or per-stack ROI boost raises or lowers how often a team or player lands in your top lineups.
• Favorite the builds you want, hit export favorites, and send them straight to DraftKings or FanDuel.

Watch The Video

Prefer to follow along on screen? Here is the full walkthrough of the pre-contest sims tool.

Watch on YouTube

What The NFL DFS Contest Simulator Actually Does

An optimizer builds lineups. The simulator judges them. Once you have a pool built in the Stokastic Sims workflow, you open the pre-contest simulator tab and your lineups are already loaded, up to 500 on the base package or up to 10,000 on the top package. Press run contest simulation and a couple of minutes later every lineup has been played against all the others across tens of thousands of simulated contests, and each build comes back with a full-field simulated ROI, win rate, and cash rate instead of just a projected score.

That difference from a plain optimizer is why we treat the simulator as the last step before you enter, not the first. If you are still deciding whether to lean on sims at all, our breakdown of DFS sims vs optimizers covers why the field-level view wins tournaments. Here we assume you are past that and ready to read the output.

Set Your Inputs: Lineups, Projections, And Site

Three inputs decide everything the simulator hands back.

Your lineup pool. If you built lineups in the contest generator, they carry straight into the simulator, no re-upload needed. You can build up to 500 lineups in the generator on the base package. You can also bring your own lineup file: save it, upload it here, and simulate those instead.

Your projections. By default the sim runs on Stokastic projections, the same NFL DFS projections, ownership and stacks in the DataHub that feed the rest of the build. If you would rather trust your own numbers, click use custom projections, download the template, drop your projections into the file, and upload it back. The simulator then runs the whole field on your inputs, which is a clean way to stress-test your own model against ours.

Your site. Set the slate to DraftKings or FanDuel so the scoring, salaries, and export format match where you are actually playing.

Quick tip: The custom-projections upload is the fastest way to A/B test your own model. Run the same lineup pool once on Stokastic projections and once on your numbers, then compare the simulated ROI leaders side by side.

Get these three right and the columns that follow mean something. Get them wrong and you are ranking the wrong lineups perfectly.

Run The Simulation And Read The Columns

With inputs set, run the sim. The default sort is simulated ROI, and that default is deliberate: it is the return each lineup earns against the rest of the simulated field, and it is generally the best single number for choosing what to play. Each core column is telling you something specific.

The row worth staring at is any lineup with a strong simulated ROI but a low ownership sum. That is a build the field is not on, ranked highly by the sim anyway, and it is exactly the kind of leverage a large-field tournament pays for. A "naked QB" build, like the Jalen Hurts lineup shown with none of his own pass catchers, has no stack type to report, since there are no pass catchers to count, and the sim will tell you fast whether that unstacked approach is helping or hurting relative to your stacked builds.

The One Setting Most People Skip: Match Percent-to-First To Your Contest

This is the lever promised up top. Above the results sits a percent-to-first selector, and it quietly reorders your entire lineup list. Set it to the share of the prize pool that first place actually takes in the contest you are entering.

In a flat contest where first place takes only a small slice of the pool, like a double-up where roughly the top half of the field all wins the same amount, set it low, around 5 or 10 percent, and the sim rewards high-floor, high-cash-rate lineups. In a top-heavy tournament, push it up to 20, 25, or 30 percent so the sim rewards the ceiling builds that actually take down first place. For instance, a DraftKings NFL Millionaire Maker with $1 million to first out of a $5 million prize pool is exactly that top-heavy: first place is 20 percent of the pool, so you would select the 20 percent option to make the simulator score lineups the way that contest actually pays. Whatever the specific pool, the move is the same, read first place's share off the payout tab and match the setting to it. Get this right for your own Milly Maker build and the whole ranking changes underneath you.

This is the setting most players leave on default. Because the amount that goes to first place changes which lineups win, the same pool sorted for a flat double-up and sorted for a Milly Maker are two different lists. Set it before you favorite a single build.

The one-line version: Match percent-to-first to your contest before you sort. Keep it low for double-ups, push it to 20 percent or higher for a top-heavy Milly Maker, and let the sim re-rank your pool for the contest you are actually entering.

A Worked Example: Shaping Exposures With ROI Boosts

Sorting is step one. Shaping is where the tool earns its keep, and you can do it without rebuilding a thing. Walk through the sample build from the video to see the controls in action, using its actual numbers.

Say the sim is landing a defense in 34 of your top 150 lineups and you want less of it. Give that team a negative ROI boost, click boost ROI, unfavorite the lineups, re-sort by simulated ROI, and reselect your top group. In the sample build a -10 boost pulled that defense back, and cranking it to -60% brought it down to roughly 22% of your top 150. The stack boost works the same way in the other direction: want more of a specific offense, or fewer of one quarterback's stacks? Nudge that team's stack boost up or down and the sim rebalances how often it appears. These boosts live alongside the rest of the Stokastic Sims settings, so you can shape a pool without ever reopening the optimizer.

Then read the diagnostic tabs to see who is driving your ROI:

• Player ROI ranks every player by simulated ROI across the lineups that contain them. In the sample build one receiver posted a 52.8% ROI, a quarterback sat at 47.8% ROI, and the least profitable player checked in around a -81.1% ROI. Fade the bottom of that list.
• Stack ROI does the same for stack types. The least valuable QB+1 single stack in that build belonged to one quarterback, while a different quarterback led the most valuable, and there is usually some correlation: a profitable QB+1 stack tends to be a profitable QB+2 and QB+3 too. If you are still deciding which correlations to chase, our NFL DFS stacking guide covers which pairings actually pay.
• Exposures shows your overall lean on each player alongside leverage, the gap between the field's projected ownership and your own. In the sample build one receiver topped that list, landing in 27.3% of the lineups. Sort by negative leverage to see who you are underweight instead: a back projected for 13.6% ownership that you have in only 4.7% of lineups is a player you are quietly rooting against.

Notice the callback to that ownership-sum column from earlier: leverage is that same idea applied player by player, and it is how you turn a good pool into a differentiated one.

Dupes: Why Showdown Is Different From The Main Slate

The dupes column measures how many other entrants are likely to submit an identical lineup, and on a full NFL Sunday main slate it barely matters. The player pool is so large that your builds come out fairly unique on their own. Single-game formats are the opposite. On a DraftKings Showdown or single-game slate the small pool makes duplicate lineups spike, and a lineup duped 40 times pays out very differently from one that is not duped at all. The contest generator can build showdown lineups to a target dupe level on purpose, and that shows up in this column and in the ROI the sim reports. So watch dupes closely on showdown, and largely ignore them on the main slate.

Export And Enter

When your favorited list looks right, hit export favorites. You get a file of every lineup you selected, ready to upload straight to DraftKings or FanDuel and enter into your contests. That closes the full loop: build, simulate, match the payout, shape exposures, export.

Where The Edge Actually Comes From

Step back and the reason this tool wins is simple. Picking "the best players in good matchups" is what everyone in your contest is already doing, and their projections look a lot like yours. The edge is not in the projections, it is in construction: knowing which of your hundreds of possible lineups actually win the specific contest you are entering, and reading which players and stacks are carrying that ROI so you can lean in or fade. The simulator is the only step that answers that question against the real field. Run it on your next slate, set the percent-to-first to the contest you are playing, and let simulated ROI pick your builds.

Ready to run your own NFL DFS contest simulations? The full Contest Sims live in the Stokastic NFL package: the base Data + Sims tier lets you export up to 20 lineups at a time, and Sims MAX unlocks the full 10,000-lineup simulations with unlimited exports. Want to kick the tires first? You can try the Sims free before you commit. Code NFLCONTEST10 takes 10% off your first payment.

Get the Stokastic NFL package

Frequently Asked Questions

What is the difference between the optimizer and the contest simulator? The optimizer builds lineups from your projections and rules. The contest simulator takes that pool and plays it against itself across tens of thousands of NFL DFS contest simulations, then ranks each build by simulated ROI, so you enter the lineups that win money against the field rather than the ones that just score the most points on paper.

Do I have to use Stokastic projections? No. The sim runs on Stokastic projections by default, but you can click use custom projections, download the template, drop in your own numbers, and simulate the field on your inputs instead.

Why does percent-to-first matter so much? It tells the simulator how top-heavy your contest is. A flat double-up and a top-heavy Millionaire Maker reward different lineups, so matching this setting to your contest's real payout reorders which builds the sim recommends.

Does the contest simulator work for Showdown? Yes. Single-game and Showdown slates are fully supported, and dupes matter far more there than on the main slate because the small player pool makes identical lineups common. See our Showdown strategy guide for how to attack single-game builds.

How many lineups can I simulate and export? You can simulate up to 10,000 lineups on the top package. The base Data + Sims tier exports up to 20 lineups at a time, while Sims MAX lets you export as many as you like straight to DraftKings or FanDuel.