Unusual Weapon Size: Cost and Weight

[DanMcS]

The PHB specifies that a large weapon costs double the medium version, and weighs twice as much. A small weapon costs the same as the medium, but weighs half. It doesn't go any further than that, though there are rules for extrapolating damage for huge, gargantuan, colossal, tiny, diminutive, and fine weapons, just not their cost or weight.

Is there a rule of thumb for this that I'm missing somewhere, or would it be fair to use the costs and weights from the armor for unusual sized creatures table?

 

[Altamont Ravenard]

The Arms and Equipment guide states that larger weapons weigh +50% for each size category increase, and the price follows. For smaller weapons, cost and weight are reduced by 25% for weapons smaller than small. Range increments are modified by 25% for each size increase/decrease.

AR

 

[DanMcS]

The Arms and Equipment guide states that larger weapons weigh +50% for each size category increase, and the price follows. For smaller weapons, cost and weight are reduced by 25% for weapons smaller than small. Range increments are modified by 25% for each size increase/decrease.

AR

Mmpm, thanks. Is it the normal stacking rule for D&D, or do they really mean increase by 50%?

IE, if a large weapon costs 100gp, a huge is +50%, that's 150gp. Is gargantuan 200gp or 225gp?

Similarly for tiny, diminutive, and fine, I guess. Does it go 100% small, 75% tiny, 50% diminutive, 25% fine? That would seem to be the easiest.