Game contribution
Contribution is the share of each coin you stake that counts toward a wagering requirement. It is the most consequential number on a promotion, and the one most often left out of a comparison.
If a game contributes 100%, every coin you stake counts in full toward the requirement. If it contributes 20%, five coins must be staked for one to count. The requirement has not changed. The amount of play needed to satisfy it has been multiplied by five.
This matters because the house edge applies to what you actually stake, not to what gets credited. Multiplying the play multiplies the cost.
Contribution divides
T = R ÷ c
expected cost = (R ÷ c) × h
R is the requirement in credited coins, c the contribution, and T what you actually have to stake. Halving the contribution doubles the cost; dropping it to 20% multiplies the cost by five.
The same requirement at different contribution rates
A 100 SC balance with a 2x requirement, played at an assumed 96% RTP. Only the contribution changes between rows.
| Contribution | Must actually stake | Expected loss | Expected balance | Break-even multiplier |
|---|---|---|---|---|
| 100% | 200.00 SC | 8.00 SC | 92.00 SC | 25x |
| 50% | 400.00 SC | 16.00 SC | 84.00 SC | 12.5x |
| 20% | 1,000.00 SC | 40.00 SC | 60.00 SC | 5x |
| 10% | 2,000.00 SC | 80.00 SC | 20.00 SC | 2.5x |
| 5% | 4,000.00 SC | 160.00 SC | None — exhausted | 1.25x |
Note the last row
At 5% contribution, a 2x requirement is expected to consume the entire balance — the break-even multiplier has fallen to 1.25x, below the 2x being asked. The promotion looks identical to the one in the first row. The contribution percentage, usually buried in a terms page, is the whole difference.
What to check before you play
Contribution is usually stated per game category rather than per game, and the categories are the operator’s own. A few things are worth reading carefully:
- Excluded games contribute nothing. No amount of play on them advances the requirement, and the coins are still spent. This is different from a low contribution — it is a contribution of zero, which no finite amount of wagering can satisfy.
- Categories can be broader than they look. “Table games” often covers video poker and some slot-shaped games.
- Mixing games mixes rates. The calculators here take a single contribution rate. If you play across categories, the true figure sits between the rates you used, weighted by how much you staked at each.
- Contribution can change mid-promotion at some operators. The rate that applies is the one in force when the wager is placed.
Playthrough calculator — how much you must stake at a given contribution. · Worked example: why a 20% game costs five times as much