An extra place calculator is how matched bettors turn bookmaker extra-place offers into profit. The bookie pays four places on a race; the exchange place market only pays three. Back a horse each way at 12/1, lay the win and the place at the exchange, and you’ll lose about 90p whatever happens, unless the horse finishes 4th. Then the bookie pays the place, the exchange place lay wins as well, and you collect around £33. The free calculator works out both lay stakes and every outcome for you.
How the extra place calculator works
You’re running two lays at once. The win part of your each-way bet is laid in the exchange win market. The place part is laid in the exchange place market, using the bookie’s place odds (a quarter or a fifth of the win odds).
Place back odds = 1 + (odds − 1) × terms Lay stake = back stake × back odds ÷ (lay odds − commission)
That gives you four outcomes: the horse wins, it places inside the exchange’s places, it lands in the extra place only, or it’s unplaced. The first, second and fourth should all come out at a small loss. The third is where the money is.
Picking races
The best extra-place races have a fairly small field (8 to 12 runners), a horse at mid-range odds of about 8/1 to 16/1, and a tight gap between the bookie’s odds and the exchange lay odds in both markets. The place market is usually the thinner one, so check its liquidity before you commit. A qualifying loss of 3% to 5% of the total stake is reasonable; much more and the race isn’t worth it.
The win-only version of all this is in the matched betting calculator, and plain lay bets are in the lay calculator. For golf, where extra places come round every week, the golf each way calculator covers dead heats.
Bet with money you can afford to lose. If it stops being fun, BeGambleAware.org is free and confidential.