Classification
Fair and meaningful competition
Classification groups athletes of similar body size so that competition is fair and results are meaningful. Athletes are classified by measurement, not by diagnosis: arm span decides the upper-body class and leg length decides the lower-body class, and athletes with any form of dwarfism are classified in exactly the same way.
This page summarises Part 2 of the 2026 IDSF Rule Book. The 2026 IDSF Rule Book was adopted by the IDSF Board on 18 October 2026. Where this summary and the rule book differ, the rule book applies.
Check your own class
Enter your measurements to see your age group, whether you are eligible, and your classes. Nothing you enter is stored. The result is a guide only: your official class is set by a Classification Officer.
How athletes are measured
A recognised Classification Officer, or the IDSF panel of Classification Officers at the Games, measures every athlete barefoot, to the nearest half centimetre: standing height, sitting height, and arm span from fingertip to fingertip with the arms level at shoulder height.
Leg length is not measured directly. It is standing height minus sitting height.
Arm span decides the upper-body class, which applies to sports such as swimming and field events. Leg length decides the lower-body class, which applies to sports such as track events, badminton and table tennis. The two are decided separately, so an athlete can be Class 2 upper body and Class 3 lower body. Each sport's rules say in which divisions its classes are used.
Archery, boccia, kurling and shooting use no classes. Powerlifting uses body-weight categories instead.
A measurement exactly on a boundary falls in the class whose range includes that value.
Standing height is also checked against the eligibility limits below.
Who is eligible
| Sex | Disproportionate dwarfism | Proportionate dwarfism |
|---|---|---|
| Men | 157.5 cm | 152.4 cm |
| Women | 152.4 cm | 147.3 cm |
An athlete taller than the limit for their sex and type of dwarfism cannot compete. The limits are exact: 152.5 cm is over a 152.4 cm limit. Athletes with proportionate dwarfism must provide a doctor's letter or diagnosis document proving their genetic condition when they are classified. In a borderline case, the Classification Officer decides whether an athlete's dwarfism is proportionate or disproportionate.
Open and Masters divisions
| Group and measurement | Class 1 | Class 2 | Class 3 | Class 4 |
|---|---|---|---|---|
| Men — arm span | Up to 113.5 cm | 114–129 cm | 129.5–151.5 cm | Over 151.5 cm |
| Men — leg length | Up to 42 cm | 42.5–47.5 cm | 48–56 cm | Over 56 cm |
| Women — arm span | Up to 102 cm | 102.5–117.5 cm | 118–140 cm | Over 140 cm |
| Women — leg length | Up to 37.5 cm | 38–44 cm | 44.5–52.5 cm | Over 52.5 cm |
Class 4
Class 4 is the class for the longest arm span or leg length. It is used in the Open and Masters divisions and in the Junior 7–11 and Junior 12–15 age groups, but not in junior track and field or swimming.
In team sports, Class 4 athletes may only play part of a game: the first two quarters in basketball, the first third in floor hockey, the first half in football and the first set in volleyball.
Juniors
Juniors (ages 7 to 15) are classified by measurement too, with their own thresholds for each age group. Junior 7–9, Junior 10–12 and Junior 7–11 use one set of thresholds for boys and girls; Junior 13–15 and Junior 12–15 have separate ones.
Age is counted by year: your age is the year of the competition minus the year you were born. A junior who competes in the Open division keeps the thresholds of their own junior age group.
Futures (age 6 and under) are not classified.
Juniors: track and field and swimming
| Group and measurement | Class 1 | Class 2 | Class 3 |
|---|---|---|---|
| Junior 7–9, boys and girls — arm span | Up to 86.5 cm | 87–98 cm | Over 98 cm |
| Junior 7–9, boys and girls — leg length | Up to 30.5 cm | 31–35.5 cm | Over 35.5 cm |
| Junior 10–12, boys and girls — arm span | Up to 96.5 cm | 97–110 cm | Over 110 cm |
| Junior 10–12, boys and girls — leg length | Up to 35.5 cm | 36–41 cm | Over 41 cm |
| Junior 13–15, boys — arm span | Up to 106.5 cm | 107–122.5 cm | Over 122.5 cm |
| Junior 13–15, boys — leg length | Up to 39 cm | 39.5–45 cm | Over 45 cm |
| Junior 13–15, girls — arm span | Up to 99.5 cm | 100–116 cm | Over 116 cm |
| Junior 13–15, girls — leg length | Up to 37 cm | 37.5–43 cm | Over 43 cm |
Juniors: all other sports
| Group and measurement | Class 1 | Class 2 | Class 3 | Class 4 |
|---|---|---|---|---|
| Junior 7–11, boys and girls — arm span | Up to 89.5 cm | 90–102 cm | 102.5–119.5 cm | Over 119.5 cm |
| Junior 7–11, boys and girls — leg length | Up to 32 cm | 32.5–37.5 cm | 38–44.5 cm | Over 44.5 cm |
| Junior 12–15, boys — arm span | Up to 105.5 cm | 106–121 cm | 121.5–143.5 cm | Over 143.5 cm |
| Junior 12–15, boys — leg length | Up to 38.5 cm | 39–44 cm | 44.5–52.5 cm | Over 52.5 cm |
| Junior 12–15, girls — arm span | Up to 98.5 cm | 99–115 cm | 115.5–138.5 cm | Over 138.5 cm |
| Junior 12–15, girls — leg length | Up to 36.5 cm | 37–42.5 cm | 43–51 cm | Over 51 cm |
Where and when to be classified
If your country has a recognised Classification Officer, report to them before the entry deadline. They take your measurements and send them to the IDSF Chief Classification Officer.
If your country has no Classification Officer, your national association must contact the Chief Classification Officer before the entry deadline. You are then classified by the IDSF panel at the World Dwarf Games registration, before your first event.
How long a classification lasts
For athletes over 21, a classification is permanent. You must report any significant change that may affect it, such as a late growth spurt or medical treatment.
For athletes aged 21 and under, a classification is valid for four months from the day of measurement. If it is older than that when a competition starts, the athlete must be measured again.
Every athlete must be measured again whenever the IDSF changes the classification system. IDSF reviews the thresholds after every World Dwarf Games.
Checks and protests
The competition host may measure athletes at random or for a reason, for example when an athlete's arm span or leg length is far outside the range of their class.
A country's chef de mission or head coach can protest an athlete's class in writing, with a protest fee of 100 US dollars that is returned if the protest is upheld. The Protest Committee's decision is final.
What changed in 2026
The previous thresholds had no traceable source, and juniors had no measurement-based classes, so a junior's class depended only on their condition. Since 2026 every class, including Class 4 and the junior classes, is set by arm span and leg length, and every threshold is calculated from the published Achondroplasia Growth Charts.
Because the classification system has changed, every athlete must be measured again.