Betfair Back–Lay Arbitrage

Back Odds (decimal)

Back Stake

Lay Odds (decimal)

Code (sets commission)

Commission (0–20%) Applied to **net winnings** on Betfair.

Calculated Lay Stake

StatusEnter inputs

Liability (if selection wins)—

Guaranteed Profit—

ROI—

Arb condition (with commission c): BackOdds > (LayOdds − c) / (1 − c).