How are the weights determined in a handicap?

How are the weights determined in a handicap?  Approximately 60% of all horse races run in Britain each year are handicap races, in which the weight carried by each horse is determined by the race conditions and by the official handicap ratings of the participants. Official handicap ratings, which are awarded after a horse has won a race or, failing that, has raced at least three times, represent, numerically, its level of ability in eyes of the handicappers at the British Horseracing Authority (BHA).

The highest, and lowest, weights to be carried are specified in the race conditions, along with a range, or band, of handicap ratings within which eligible horses must fall. Obviously, the horse with the highest handicap rating carries the highest weight. Thus, in a hypothetical 0-60 handicap, a horse rated 60 would carry the highest weight of, say, 9st 7lb, and so on down the weights. If the minimum weight was 8st 7lb, the lowest-rated horse in the handicap proper would be rated 46.

Of course, horses rated 45 or lower can still be entered, but are required to carry the minimum weight, so are said to be ‘out of the handicap’. Likewise, horses rated 61 or 62 can also be entered, but can only be accommodated if the number of entries rated 60 or lower is below the safety limit for the race in question. In this example, such horses would be required to carry 9st 8lb or 9st 9lb or, in other words, 1lb or 2lb more than the specified maximum weight.