A dead heat is calculated by dividing the stake proportionally between the number of winners in the event. So, in a two-way dead heat (2 winners) for example, your return will be half of what it could have been. This can be referred to as half-face value of the bet, or a bet for half the original stake.
For example:
Initial bet = £30 @ 11 (1 expected winner - 2 dead heat for first)
Half-face value of ticket: £30 @ 11 divided by 2 = £165
or
Half-stake: £15 @ 11 winning bet = £165
The profit of the bet equals the total return minus total stake: £165 - £30.00 = £135
When there are multiple payouts, this can get quite confusing.
In a golf tournament, Tiger Woods wins, Vijay Singh finishes second, Phil Mickelson third, but five players tie for fourth. This creates a multiple dead-heat for fourth and fifth place.
So in this case, if you backed Luke Donald for £5 at 10.0 for a Top 5 finish and he finished in the tied group of players, you would receive
Stake x Odds x No. of Payouts / No. of Tied runners = £5 x 10.0 x 2 / 5 = £20
In order to calculate your profit, dont forget to minus your original stake.