House Edge & Expected Loss
House edge is the casino's mathematical advantage. Learn how to calculate expected loss from your stake, spin speed, and the slot's RTP.
Last updated: May 2026 · 18+ educational content
Key takeaways
- House edge = 100% − RTP. A 96% RTP slot has a 4% house edge.
- Expected loss = stake × spins × house edge.
- Spin speed multiplies your loss faster than bet size in many cases.
- No system, pattern, or bet structure changes the house edge.
The formula
Expected loss = bet size × number of spins × house edge
Worked examples
- $0.50 × 600 spins × 4% = $12 expected loss per hour
- $2.00 × 600 spins × 4% = $48 expected loss per hour
- $2.00 × 600 spins × 8% = $96 expected loss per hour
Why spin speed matters
Online slots can spin in under 3 seconds — that's 1,200+ spins per hour with auto-play. Your hourly expected loss scales linearly with that count. Slowing down is one of the few things you actually control.
"Systems" do not work
Martingale, Fibonacci, "after X losses, double up" — none of these change the house edge. They only change the shape of your loss distribution, usually making rare catastrophic losses more likely.
Related
Read about RTP and volatility, then set a budget on the responsible play page.