# Can You Calculate a Slot Machine’s Payback Based on a Single Session?

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The payback percentage of a slot machine is not something readily available, so many players try to figure ways to determine what the machine’s payback will be. The idea has come up for some that if you can figure your coin in and out of a single machine, you can determine the machine’s payback. Is this true?

STATUS: Sadly, no. Your session is not necessarily predictive of long-term payback.

A slot machine’s math is designed to reach its programmed expected payback over millions of spins and a long-term approach. In the short term a jackpot or a dearth of winning spins can swing the payback in one direction or the other.

As such, using your own session data to determine the payback will only be informative to what your session’s payback provided you, not the overall payback of the machine.

There are a couple of ways you might be able to determine it, but it isn’t a blanket opportunity and has a caveat:

• Some players have reported their hosts can share their theo number, which is the theoretical loss based on their games played and their payback percentages. If you played a single game the entirety of your time there, at the same denomination, you’d be able to confirm that particular configuration. Keep in mind that even changing games within the same machine, or different denominations, could impact the final number, as it would be a weighted average of your play.
• Certain casinos, such as Venetian/Palazzo, have you generating points based on the theoretical hold of the machine. If you’re able to track each machine you should have a good sense of the payback of one vs. another.
• Both of the above presume the systems used for player tracking has an accurate assessment of what the machine’s expected payback is, which isn’t always the case.

This doesn’t really give you much to work with, unless you have access to precise information in a controlled environment.

Likely more helpful is if you’re playing in a market were slot payback reporting is available; you might not get a per machine understanding, but you’ll know the general idea of what to expect. Or if you’re playing at a company with lots of properties, looking at properties that must report will hint at what others pay since they likely have a corporate mandate to follow.