Weight for age and how the WFA scale sets each horse's weight

Weight for age (WFA) is a set of race conditions in which every horse carries the weight a published scale sets for its age and sex, at that distance and in that month. No runner carries extra for being better than the others. In Australia the scale is AR 168 of the Australian Rules of Racing (as at 1 October 2026). In a 1600m race in October it gives a three-year-old colt 51kg and a five-year-old gelding 59kg, and fillies and mares carry 2kg less than males of their age.

The scale exists because young horses are still maturing. It gives a three-year-old a large allowance in spring and takes it back month by month until the horse turns four. Nearly half of all Group 1 races are run at WFA, so it shapes many of the season's biggest races.

How the weight for age scale works

AR 168 sets weights in six distance bands from 1000m to 3200m, for every month from August to July and for ages two, three, four and five-and-older. Ages count from 1 August under AR 161, which is why the scale's year starts in August (racehorse birthday explains the rule). An extract for spring, in kilograms:

Three patterns run through the full table:

• Horses aged five and older carry the same weight all year, from 58.5kg in the shortest band to 59.5kg in the longest.
• The longer the race, the bigger a young horse's allowance. In October a three-year-old gets 58.5 - 53 = 5.5kg from males five and older up to 1200m, but 59.5 - 49 = 10.5kg over 2400m to 3200m.
• Two-year-olds appear only from January, starting at 45kg over 1000m to 1200m.

Fillies, mares and northern hemisphere horses

AR 168 allows fillies and mares 2kg "from 1 August to 31 July", so a five-year-old mare carries 57kg where a gelding of the same age carries 59kg over 1200m to 2400m. The rule states no reason for the 2kg. AR 169 gives the same 2kg in set weights and set weights and penalties races, except races confined to fillies and mares.

AR 170 adds a separate allowance in standard weight-for-age races for horses sired in the northern hemisphere and foaled between 1 January and 31 July. AR 161 counts the age of a January to June foal from the 1 August before it was born, so such a horse's official age runs ahead of its real one, and the allowance offsets that. Over 1200m to 1600m in October it is 2.5kg for a three-year-old and 1kg for a four-year-old, and for four-year-olds it is gone by May at every distance.

Worked: a three-year-old's allowance through spring

The scale assumes a three-year-old gains 9 - 3 = 6kg's worth of maturity between August and March. In September a three-year-old colt is beaten 1.5 lengths by a six-year-old gelding over 1600m at WFA, receiving 8.5kg. They meet again over the same trip in December, when the colt receives 6kg, which is 2.5kg less.

At the British Horseracing Authority's 1-mile average of 2lb, or 0.9072kg, a length (the range is set out in weight in horse racing), 2.5kg is 2.5 / 0.9072 = 2.76 lengths. If neither horse improves, the gelding should now win by about 1.5 + 2.76 = 4.26 lengths. To reverse the result the colt has to improve by more than 4.26 lengths in three months, 2.76 of them just to keep pace with the scale.

The same reading works for the Cox Plate, a 2040m weight-for-age race in late October. The over 2000m to 2400m band has three-year-old colts on 49.5kg against 57.5kg for four-year-old males and 59kg for males five and older, a 9.5kg allowance from the oldest. Cox Plate betting covers that race.

Weight for age against set weights and handicaps

Under set weights the conditions fix each runner's weight, with kilos added for past wins in set weights and penalties races, and in a handicap the best horse carries the most. Racing Victoria's rules count a race as weight for age even with penalties or allowances added, or when it is confined to one age, so read the conditions line, as how to read a form guide explains.

Racing Australia's 2025-26 list of Group, Listed and Restricted Listed races shows where WFA sits:

That is 36 / 76 = 47.4% of Group 1s against 9 / 267 = 3.4% of Listed races. Of the list's 78 weight-for-age races, 36 / 78 = 46.2% were Group 1s, more than at any other level, which fits Racing Victoria's description of WFA races as primarily run at Group 1 level. Of the other 40 Group 1s, 24 were set weights races and 13 handicaps, so WFA was the most common Group 1 condition.

A three-year-old also gets far more at weight for age than in a handicap. At 1600m in October (the over 1400m to 1600m band) the scale gives it 59 - 51 = 8kg from males five and older. Racing Victoria's handicapping policy (checked October 2026) gives 3.5kg in a metropolitan Benchmark 70 to 84 handicap over 1401m to 1600m from August to October.

Why WFA races are true tests, and how they bet

In a handicap the best horse is weighted to give the others a chance. At weight for age it carries only what the scale sets for its age and sex, so the class gap the form shows stays in the race. Racing Victoria's handicapping page gives an example. When Nature Strip won the 2021 VRC Sprint Classic, a Group 1 at weight for age, he was rated 11 points above his nearest rival, which would have meant 5.5kg more in a handicap. Racing Victoria says the conditions "advantaged him enormously", and the win did not raise his rating. On the range of about 0.91kg to 1.55kg a length, 5.5kg is worth 5.5 / 1.5468 = 3.56 to 5.5 / 0.9072 = 6.06 lengths.

That shapes the betting in three ways:

1. The market tends to be tight at the top, with a short-priced favourite and money concentrated on a few runners, where a handicap spreads it (handicap races shows that shape). To check, compare favourites' starting prices in WFA and handicap races on the same carnival cards over a season.
2. Start from class and ratings, adjusted to today's scale weights, rather than from the weights themselves.
3. Small errors cost more at short prices. With illustrative numbers, say you rate a WFA favourite a 55% chance. At $1.90 the expected value of a $10 bet is 10 x (0.55 x 1.90 - 1) = +$0.45, and at $1.70 it is 10 x (0.55 x 1.70 - 1) = -$0.65. If the true chance is 50%, the $1.90 bet is worth 10 x (0.50 x 1.90 - 1) = -$0.50.

Famous weight for age races

Racing Australia's 2025-26 list includes these weight-for-age Group 1s; names, dates and conditions can change, so check the current year's list:

Group and Listed races explains how a race earns its status, and The Everest betting covers the richest race on the list.

Mistakes people make with weight for age

1. Comparing a three-year-old's spring and summer form against older horses without the scale. The colt beaten 1.5 lengths at 8.5kg in September is 2.5kg worse off by December.
2. Treating WFA form as handicap form. A horse rated 11 points above its rival can win easily at WFA and find 5.5kg more a different matter in a handicap.
3. Counting the mares' 2kg as an extra edge. It is already in the scale.
4. Forgetting the northern hemisphere allowance for a horse foaled between January and July.
5. Assuming a short WFA favourite is a good bet. At $1.70, a 55% horse loses 65 cents for every $10 staked, on average.

Comparing WFA prices with B337

At weight for age the gap between your price and the market's is often narrow, so the price you take matters more. B337 does not rate horses: there is no ratings engine, no model and no selections. The Terminal shows prices from 40+ bookmakers across racing and sports side by side, with the best available price on each runner picked out and Betfair back and lay alongside. Its EV overlays compare each price with an estimated fair price from Betfair's market, an estimate rather than a forecast.

Prices are collected on a repeating cycle, not tick by tick, so confirm a price in your bookmaker account before betting. Not every bookmaker prices every race: the columns follow the market. A free account opens a limited view of the Terminal with live odds; Betfair prices and EV overlays start at Terminal View. Betfair is a trade mark of its owner, and B337 is not affiliated with it. For free and confidential support call 1800 858 858 or visit gamblinghelponline.org.au.