How Slot Machine Reels Work: Types, Mechanics & Modern Features

RNG & Virtual Reels (the real mechanism)

A Random Number Generator (RNG) decides how slot machine reels determine payouts for online games. This software literally randomizes results by generating the outcome after the player spins the reels and before the slot symbols show the outcome.

1. The RNG is always active and is not on/off

2. Each random number links to a reel position

3. You’ll see the visible virtual reel, but only a part of it

4. The virtual reel has a stop map that links to what you see on the screen.

Weighted Reels & Why ‘Near Misses’ Happen

Weighted slot reels give symbols separate hit frequencies, which provides some games with near-miss mechanics. If you play a slot with lots of near misses, this is just a tease feature because the symbols are set to land at different intervals.

1. High-value symbols appear less often

2. Low-value symbols are more common

3. Weighted reels bring more tension to slots

4. The outcome is still handled by the RNG

Hit Frequency & Volatility

Hit frequency and volatility show you how often a slot game wins and how much the payouts can be. If you’re getting regular small wins as you play, this shows the hit frequency is high, and the volatility is low. When you don’t get many wins, but the payouts are bigger, you’re playing a low-frequency slot with high volatility.

• The hit frequency is a percentage that shows how often a lot wins, but not the payouts.

• Volatility shows the general behavior of payout results.

  • Low volatility slots have higher frequencies, paying out a lot by smaller amounts.

  • High volatility slots are low frequency because they pay less frequently but higher amounts.

What Matters More Than Reel Count

RTP, volatility, bet amounts, and paytables can have a bigger impact on payouts than the slot reels themselves. If you want a complete idea of the payout potential of a slot, look at these four:

1. RTP shows how much a slot pays back over the long term.

2. Volatility is the payout structure.

3. Paytable tells you how much symbol combos and bonuses pay.

4. Bet configuration tells you how much you can bet per spin.

Cascading/Tumbling Reels

Cascading reels, which are also known as falling, avalanche, or tumbling reels slots, remove winning symbols and replace them with new ones. This keeps happening until there are no more wins, allowing players to create colossal winning streaks from a single spin. Examples include the jungle -themed slot, Gonzo’s Quest, Sweet Bonanza, and Reactoonz.

Copy Reels

Copy reels do what they say on the can and replicate symbols onto a secondary grid. If one reel copies itself to another section, you can get bigger payout potential from symbol combinations. Examples include Jammin’ Jars, Mental, and Razor Shark.

Expanding Reels/Reel Modifiers

Expanding reels and reel modifiers make changes to symbol behavior, reel size, and how the reels work. If a reel expands or modifies, you get more coverage to potentially hit bigger wins. Examples include Big Bass Bonanza and Megaways slots.