Short answer: The optimal lineup is the single highest-scoring lineup you could legally have built from a slate, given the salary cap and the roster rules. It is worked out after the fact from what actually happened. On its own it is hindsight, but comparing your lineup to the optimal is one of the best ways to see where you left points on the table and get better.
What "optimal" actually means
A slate has a huge number of possible lineups, but only some are legal: they fit under the salary cap and fill the required roster slots. The optimal is the best-scoring one of all those legal lineups, using each player's real final score. It is not a projection and not a guess, it is the mathematically best valid lineup in hindsight. Working it out properly is a real optimisation problem, not simply picking the top scorers, because you have to stay under the cap and fill every slot.
Why it is useful
You will almost never build the optimal, and that is fine, nobody does it consistently. Its value is as a benchmark:
- See the gap. How far your lineup finished behind the optimal tells you how much room there was.
- Spot the misses. The players in the optimal that you faded, or the cheap piece that unlocked the whole build, are the lessons for next time.
- Sharpen roster construction. Over a season, comparing your builds to the optimal teaches you where your process leaks points.
How LiveSlates shows it
LiveSlates works out the optimal lineup for your slate and shows it live and after the games, so you can see the ceiling you were playing against and exactly where your lineup fell short. It sits alongside your live points and pace, so the sweat and the learning happen in the same place.
See it live
See the optimal update on a replayed slate at the NFL demo.
Common questions
Is the optimal a prediction? No. It is worked out from final scores, so it is a hindsight benchmark, not a projection.
Can I ever build the optimal? Almost never, and that is normal. It is a yardstick for how much upside the slate had, not a target you are failing to hit.
Does DraftKings show the optimal? No. It is something a dedicated tool works out for you.