Roulette Dozens Strategy
Roulette dozens strategy bets on 1st (1-12), 2nd (13-24) or 3rd (25-36) dozen. Pays 2:1, hit rate 32.43% on European. Mid-range variance, popular target for coverage systems.
How the dozen bet works
The roulette layout has three dozens, each covering 12 numbers. Bet pays 2:1. Hit probability on European: 12/37 = 32.43%. On American: 31.58%.
Net per win: +2 units. Net per loss: −1 unit. Expected value per $10 bet: −$0.27 - same 2.70% as every other bet.
Flat dozen testing
Flat $10 on 1st dozen for 200 spins on European: expected ~65 hits, each paying $20 profit; ~135 misses, each losing $10. Expected net: 65 × 20 − 135 × 10 = +$1,300 − $1,350 = −$50. Close to the 2.70% house edge applied to $2,000 total wagered.
Single-session variance is moderate - you might see streaks of misses 5-10 long, then a cluster of hits.
Progressions on dozens
Martingale on dozens needs to recoup a loss with a 2:1 win. After a loss, the next bet only needs to be half the previous to recover, not double. The progression rule for 2:1 systems: new bet = (prior losses + base profit) / 2.
Most published 'dozen Martingale' systems get this wrong and apply 1:1 doubling, which over-bets and busts faster. Test carefully.
Two-dozen variants
Covering two dozens at once raises hit rate to 64.86%. Net per hit on the winning dozen is +1 unit (one bet pays 2:1, the other loses). Net per uncovered hit is −2 units. See Two Dozens Coverage.
Common mistake
Switching dozens based on recent results. The wheel is memoryless. Picking the 'cold' dozen has the same expected return as picking the 'hot' one.