Does betting on one number every spin work?

How Single number is played

1. Bet one unit on 17 every spin.
2. A hit pays 35:1 (+$175). Everything else loses $5.

What 20,000 sessions show

Sessions that finished ahead were up $252.73 on average; sessions that finished behind were down $668.78. 11.0% of sessions ended because the next stake no longer fit the bankroll or the table limit. 22.0% reached the 500-spin cap without hitting the target or busting.

A straight-up bet has the same expected loss per dollar as red or black but far higher variance: long losing runs are normal, and a single hit can put the session ahead. Choosing a different number changes nothing.

The median session lasted 171 spins. The median longest losing run was 64 spins in a row (the worst of 20,000 was 239), and one session in ten put at least $5 on the table in a single spin.

European versus American wheel

The same 20,000 seeds, replayed on a double-zero wheel. The second zero roughly doubles the edge to $5.26 per $100 wagered. Measured return goes from −$2.74 to −$5.13 per $100, and the mean session from −$32 to −$61.

The code that produced these numbers

This Lua is the strategy as Engineer mode runs it, inside the same sandbox and kernel. A test in the repository replays it against the bulk generator on fixed seeds and fails the build if the two ever disagree by a single dollar.

-- Single number: one unit straight-up on 17, every spin.
-- Session rules shared by every 0xroulette.com/systems page:
-- $5 unit, $500 table max, walk away at +$200, and stop the moment
-- the next stake can't be covered by the bankroll or the table limit.
local UNIT, TABLE_MAX, TARGET = 5, 500, 200

local function reset() end
local function settle(result) end

local function place(ctx)
  return { { type = "straight", pockets = { 17 }, amount = UNIT } }
end

-- Shared wrapper: enforces the session rules around place/settle.
strategy = {}
local start, stopped

function strategy.setup(ctx)
  start, stopped = ctx.bankroll, false
  reset()
end

function strategy.bet(ctx)
  if stopped or ctx.bankroll >= start + TARGET then
    stopped = true
    return {}
  end
  local bets, stake = place(ctx), 0
  for _, b in ipairs(bets) do
    if b.amount > TABLE_MAX then stopped = true end
    stake = stake + b.amount
  end
  if stake > ctx.bankroll then stopped = true end
  if stopped then return {} end
  return bets
end

function strategy.on_spin(ctx, result)
  if not stopped then settle(result) end
end

Session rules

Limitations

One bankroll, one unit size, one table limit, and one walk-away target. A bigger bankroll or a higher limit moves where a progression breaks; it does not change the return per dollar wagered. Spins are fair and independent, as on a correctly functioning wheel or a certified RNG. Physical wheel bias is a separate question, covered on Physics.

Related

• Does betting on hot numbers work?
• Does flat betting work at roulette?
• Does the James Bond roulette strategy work?
• All 20 systems, compared on the same seeds