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Simulations

What Are Simulations in DFS?

Last updated November 13, 2026 by Ship It Nation

Simulations play out a slate thousands of times using each player's range of outcomes, then record what happened. Contest sims go further and score your lineups against a simulated field to estimate how often they cash or win.

Why It Matters

A projection is one number, but a slate is many possible outcomes. Sims show which players reach the ceiling a tournament needs, how often stacks hit together, and how your lineups fare against a field playing the popular builds. They are only as good as the inputs, so a weak projection or ownership guess will produce confident but wrong results.

Go Deeper

Articles that put Simulations to work.

What Are DFS Contest Sims and How Do They Work? What Are DFS Contest Sims and How Do They Work? Lineup Building · 3 min read How to Find Leverage in DFS: A Beginner’s Guide to Beating Chalk How to Find Leverage in DFS: A Beginner’s Guide to Beating Chalk Ownership & Leverage · 3 min read

Example

Say two NFL receivers both project for 15 points. After 10,000 simulations, one goes over 30 points in 14% of runs and the other in 6%, because the first gets more deep targets. In a large tournament where you need a big score, the first receiver is the better pick even though their average projection is the same.

Pro tip

Use sims to compare close decisions, not to replace your read. If a sim result surprises you, check the input that caused it before trusting it.

Hear Us Break It Down

Hand-picked moments from our free live streams where our hosts break down this term.

Why the highest simulated ROI is not an automatic selection You distinguish results across many simulated slates from the single outcome you actually play. Before choosing the lineup with the highest simulated ROI, you also consider its projected scoring and whether it suits your contest's field size. NFL · Monday, Sep 28 56:09 ▶ How simulations help you narrow your captain choices You compare how often different captain candidates emerge across simulated outcomes, then concentrate your entries around the more frequent options. That helps you distinguish a merely possible surprise from a scenario you want to build multiple lineups around. NFL · Monday, Oct 19 38:26 ▶ Why simulated optimal results depend on the complete lineup You interpret simulated optimal appearances as part of a complete lineup, rather than treating each player as an automatic selection. That shifts your attention toward how the pieces fit together when building your roster. “That's them hitting the optimal lineup, not just them as an optimal play.” NFL · Saturday, Oct 31 31:16 ▶
More mentions 12
THU 11/12 · NFL “And if you are using SaberSim with us over at Ship It Nation for Saber Score or Contest Sim ROI, et cetera, at least you're balancing it based on the actual projection change and you're not doing too much you're just robbing scat to pay...” 26:59 ▶ MON 11/9 · NFL “What the pros did in each contest look at their player pool all of that if you're playing a couple hundred bucks a day or thousands dollars or thousands of dollars a month the contest sims and the ultimate package I know I use it hoop real...” 20:30 ▶ SUN 11/8 · NFL “He is the best leverage captain right now that we have in terms of optimal, in terms of our simulation data.” 23:00 ▶ SAT 11/7 · NFL “So I do have Contest Sims and that's where you start to see some of that stuff.” 41:53 ▶ THU 11/5 · MMA “Ultimate, it's a lot more, but if you're playing a couple hundred dollars a night, running contest sims, that is what you are seeing most of the best players in the world doing nowadays.” 40:07 ▶ WED 11/4 · NBA “This gets you contest Sims ability to build $5,000 teams, same ROIs, what Rio used to win all of the money and what a lot of people use nowadays.” 2:43 ▶ SAT 10/31 · NFL “That's how I create my field lineups for the contest sims.” 30:19 ▶ THU 10/29 · NFL “And I like them up top, but we actually have negative flex leverage on Jacobs and we have positive flex leverage on Lloyd, which obviously correlates, but sometimes it's nice to see it with the data and the simulations to actually back it.” 38:31 ▶ MON 10/26 · NFL “So the Sims, talking about the contest Sims, late swap.” 30:00 ▶ SUN 10/25 · NFL “It's so hard to tell in those situations, but I'm sure that sooner than later on X, we will have a demonstration made with AI that shows us what the Sims say.” 3:52 ▶ THU 10/22 · NFL “I think for him to get a crazy high number maybe it does end up being but I wouldn't be surprised if it's a little bit lower than that yeah I mean it's he's a home running back there's still no manung guy people are expecting it to be good...” 17:33 ▶ TUE 10/20 · NBA “Ultimate, if you're playing thousands of dollars, I do think the contest sims is something you should highly consider.” 1:01:37 ▶

Common Questions

How many simulations do you need to run?

Thousands at minimum. A few hundred runs are too noisy to separate players with similar projections. Many tools use 10,000 or more, and contest sims with large fields often need even more to give stable win and top-finish rates.

What is sim ROI?

Sim ROI is the average return a lineup earned across all simulated contests, after entry fees. A positive number means the lineup won more than it cost in the sims. It is an estimate, so treat small differences between lineups as noise.

Are DFS simulations accurate?

They are as accurate as their inputs. Sims depend on projections, outcome ranges, correlations between players and ownership guesses. Good inputs make them a strong guide for comparing options; bad inputs make them precise-looking numbers that point the wrong way.

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