How large a character is will make a number of small differences. For example, a large character's equipment will generally be larger and heavier than a similar piece of equipment sized for a smaller character.
The following table lists the various size classes, and gives modifiers for each.
| Class | Size | Damage | Weight |
| 1 | 0cm - 2cm | -10 | |
| 2 | 2cm - 5cm | -8 | |
| 3 | 5cm - 10cm | -6 | |
| 4 | 10cm - 20cm | -4 | |
| 5 | 20cm - 40cm | -3 | |
| 6 | 40cm - 70cm | -2 | |
| 7 | 70cm - 100cm | -1 | |
| 8 | 100cm - 125cm | -1 | |
| 9 | 125cm - 150cm | 0 | |
| 10 | 150cm - 175cm | 0 | 1.00 |
| 11 | 175cm - 200cm | 0 | 1.00 |
| 12 | 200cm - 230cm | +1 | |
| 13 | 230cm - 270cm | +1 | |
| 14 | 270cm - 320cm | +2 | |
| 15 | 320cm - 380cm | +4 | |
| 16 | 380cm - 450cm | +6 | |
| 17 | 450cm - 540cm | +8 | |
| 18 | 540cm - 650cm | +11 | |
| 19 | 650cm - 760cm | +14 | |
| 20 | 760cm - 800cm | +18 |
(Any race which falls outside the scope of this table have these numbers provided in the race description.)
The 'Class' column shows the size class a character of the given size falls into.
The 'Size' column shows the range of sizes which fall into the size class. A character's size is either their height or length, as appropriate. Bipeds are measured by height, while quadrupeds, fish and birds are measured by length. A character measured by length would not include any tail they might possess. A character who lies on the boundary between size classes must choose which class they wish to be in; they may not waffle back and forth depending on which is more beneficial at the time.
The 'Damage' column shows the damage bonus or penalty characters falling into this size class receive. This number is not due to the increased or decreased strength of such a character; rather it is due to the scaling of the weapon used. Thus, a character who uses a weapon sized for someone of a different size class will actually be given the damage penalty or bonus depending on the size class the weapon was designed for (although the GM may add a modifier to the skill check to reflect the added difficulty of using such a weapon). These modifiers are not applied to missile weapons, or to natural weapons (such as a character's fists, feet, claws, tail, teeth, and so on).
The 'Weight' column shows the multiplier which must be used to determine the actual weight of an item of equipment. The weights given in the Equipment chapter assume average human size (size class 10 or 11).
It is more difficult to attack an opponent smaller than your character than it is to attack one of similar or larger size. For each step in size class between two opponents beyond the first, there is a difficulty of 5 levied against the larger of the two, although this will be lessened for characters with the Fight Small skill.
Rutger (185cm tall, size class 11) is being harassed by a small bird (18cm long, size class 4). This is a difference of 7(=11-4) size classes. A single size class difference is ignored, so the difficulty is measured on 6(=7-1) size classes. Rutger will have a difficulty of 30(=5x6) in his attacks against the bird, while the bird attacks at a difficulty of 0.
The GM may wish to waive or decrease this difficulty in certain circumstances. For example, a character of size 202cm fighting a character of size 148cm might only be assessed a difficulty of 5, rather than the 10 indicated by the table, since both are very close to the border between classes.