What price a horse needs for the place half to cover your stake
If your horse places but doesn't win, the place half has to return the full £10 on its own to leave you level. A £5 stake returns £10 at evens, written 1/1, where you win the same amount you staked. So:
At 1/4 the odds, the horse needs a win price of 4/1 or bigger. At 4/1, the place half settles at 1/1 and you get your £10 back.
At 1/5 the odds, the horse needs a win price of 5/1 or bigger. At 5/1, the place half settles at 1/1.
Below those prices, a placed horse still leaves you out of pocket, as the 2/1 example shows. Above them, a placed horse returns more than your £10. At 20/1 in a race paying 1/4 the odds, the place half settles at 5/1, so a placed finish returns £30. That is why the price and the size of the field matter so much to what the place half can return.
Extra places
On selected races, a bookmaker may pay more places than the standard terms, say four places in a race that would normally pay three. The place half still settles at the stated fraction, just across more finishing positions.
Which races qualify changes from day to day and between bookmakers, so it's worth checking the place terms shown on the race before you bet.
The small print worth knowing
Dead-heats
A dead-heat is when the judge can't separate two horses at the finish. If it happens for the last paying place, the place stake is divided by the number of horses sharing that place. One part is settled at the full place odds and the rest is lost, under the dead-heat rule in Tattersalls' Rules on Betting.
For example, if Frosty Lane dead-heats for fourth with one other horse, the place stake becomes £5 ÷ 2 = £2.50. At 3/1, that returns £7.50 + £2.50 = £10. The other £2.50 of the place stake is lost.
Non-runners
A non-runner is a horse withdrawn after being entered to run. The place terms are fixed by the number of horses that actually line up for the start, so if withdrawals take a field below a threshold in the table, the terms change. An eight-runner race that drops to seven goes from three places at 1/5 to two places at 1/4.
A late withdrawal can also trigger a Rule 4 deduction, a cut to the winnings on bets already placed on the remaining runners, sized according to the withdrawn horse's price. Rain can change the going (the condition of the ground) between entries and race day, and that can lead to a wave of withdrawals.
