Some casinos DO indicate volatility, but the best way is to observe win frequency and pay table spreads. If you have lots of small pays for wins without multiplying wilds say in 0.1-20x bet range, and then a large pay of hundreds x bet for the top pays and little in between then you are likely playing a volatile game. Feature potential is another way - for example Raging Rhino you know 6-of-a-kind Rhinos pays 7.5x bet and 729 ways is achievable hence a top pay of around 5500x bet on a single bonus spin = volatile. Same can be said for Dead Or Alive or Borenanza. If you get lots of small wins of 0.5-10x bet you can likely say it's a low or low-medium variance game. There is a mathematical formula if you have access to reel maps as well as the pay tables whereby you can work out a precise volatility coefficient.
1. Say a slot has 6 reels of 10 positions, one payline and those reels only have 9 O's and 1 Seven on them you have a 10*6 chance of the single win (one-in-a-million spins, you played Bonanza?
) of 6x 7's which (if the developer set the RTP at 96% would pay £960,000). So going through all possible reel outcomes once at a level £1 bet you would have the ultimate variance figure of 1.000 and would meet the stated 96% RTP for those million outcomes.
2. Now change all the reels to 10x Sevens and play the same £1 level stake, you'd win 96p every spin, volatility thus would be 0.000 the total opposite (you've played St*rb*rst?
)
3. Now take the example 1 above and add 20 paylines. You would now get 6xSevens 20 times in the 1 million spins and thus at 96% RTP the pay would be £48,000 each time and the volatility figure would be 0.05.
4. Now let's make 16% of the RTP for a feature - the 48k above wins would now be 40k and you have non-paying scatters on the reels which could say trigger a feature where the 7's would pay scattered, and over those million spins the feature totals paid would be 160,000. You'd now have a volatility figure of around 0.00405 which is still obviously unplayably high!
This is a very abbreviated example but the principle is the same on the game you play. The calculations on them are incredibly complex with games that have billions of possible reel-stop combinations and multiple pays for scatters, 2-of-a-kinds, 3,4 and 5OAKs plus various features and wilds/wild multipliers.
So you'd likely be playing a low-volatility game if it had a figure of 0.00196 say and a very volatile one which was at 0.00374.
Now you're likely wondering what the f*** I'm on about, but I do remember some casinos did have this decimal or volatility coefficient in their game lists or descriptions a few years back and I used to wonder what on earth it meant, and maybe some still do.