Slot machine payback or payout percentage is the overall percentage that a slot machine will return to the player over the life of the machine, whether it's a land casino slot or an online casino slot. Hold percentage is the amount kept by the casino or the casino's profit.

There are many factors that are taken into consideration before the slot machines hit the casino floor. Location, competition, profit and state regulations can affect how and why a slot machine end ups with a certain payback percentage.

When land casinos purchase slot machines from the manufacturer, they order the machines with a set payback percentage. Similarly Online Casinos license the game software with a set payback percentage. Many Las Vegas casinos offer slot payback percentages in the 98% range while state operated and tribal casinos are in the 92% or lower range.

Many of the online casinos we recommend offer a 96% to 97% payback percentage. However, the Parlay Entertainment bonus slots and the traditional slots at Slotland offer games with a 98% payback.

Many slot players believe it is the slot machines Random Number Generator (RNG) that determines the payback percentage, however this is incorrect, it is the reels or reel strips that determine payback percentage. The RNG just determines which combination of symbols the spin will stop on. Change the number of times a symbol appears on a reel and you've changed the slot machines payback percentage.

When a casino wants to change the payback percentage of a slot machine they change the reels or in the case of video bonus slots, the virtual reels.

Land slot machine manufacturers send their RNG algorithm to an independent lab for testing before releasing the machines to the casinos. Similarly the software makers of online casino games do to.

The Random Number Generator (RNG) algorithm used in our recommended Real Time Gaming Online Casinos is tested for fairness and randomness on an ongoing basis by Technical Systems Testing.

Technical Systems Testing (TST), is an internationally recognized accredited testing facility. Some of their clients include International Game Technology (IGT), Aristocrat, Mikohn and the Massachusetts, Michigan and Ontario Lotteries.

Both online and land based casinos record every coin in, won and cashed out of a slot machine. Sometimes the casino floor technician needs to remove a jammed bill and the audit slip will print out. The audit slip shows the grand totals for the coins in, coins won and coins cashed out. By crunching these numbers you can get a good idea of the long-term payback percentage. However, this information is readily available if you know where to look for it.

Trusted online and land casinos hire or staff independent auditors to review this information monthly. For example Foxwoods Resort Casino publishes slot payback information in their Media Relations Press Releases and Mohegan Suns publishes it in their Slot Machine Statistical Reports.

Similarly online casino gaming manufacturers hire an independent auditing firm to review and certify the payback percentage for the casinos that license their game software.

The Vegas Technology Casinos are audited monthly for fairness of play by independent third party gaming expert, Dr. Eliot Jacobson, Ph.D and will display the Certified Fair Gambling Seal.

Some Vegas Technology Casinos that carry the Certified Fair Gambling Seal are Super Slots, VIP Slots Casino and Engish Harbour.

	Microgaming is one of the largest online casino game manufacturers and contracts the non-profit organization eCOGRA. (eCommerce and Online Gaming Regulation and Assurance) to review and certify their casino payback percentages.
eCOGRA is the independent standards authority for the online gaming industry. eCOGRA helps players identify online casino and poker sites that are safe, fair and responsible.
What does the eCOGRA Seal mean? The Play It Safe Seal is awarded to operators that fully comply with eCOGRA's strict standards for player protection, fair gaming and responsible operator conduct. Sites and their player policies are checked and rechecked on an ongoing basis to ensure their compliance with these standards, as well as your safety online. The Seal has become a homepage symbol of documented, objective, fair play.
All our Recommended Microgaming Casinos display eCOGRA Seal of Approval on the bottom of their web sites. When you click on the icon you can see the certified monthly audit reports for their casino and individual game line up.

Although playing a slot machine with the highest pay back percentage is recommended, it is not because you'll necessarily win more playing it, it is because it will eat through less of your bankroll, which in turn will give you more spins. By getting more spins out of a machine you'll increase the likelihood of hitting more winning combinations and perhaps walk away a winner.

Check out the Online Casino Slot Game Reviews and find more slot advice in our Slot Articles.

For detailed information for the online casinos with the best payback percentages download the Winning at the Slots free guide to playing online casinos.

Webmasters Join the Winning at the Slots affiliate program. It's free to join and you can earn a 66% commission.