Crafting math help

[thriceborn]

I'm putting different restrictions on magic items to lower costs, can you help me with the math. I pay three eights of the base cost to begin with cause I took the feat that lowers costs by 25%, and I'm putting skill and race restrictions on the items, lowering the cost by 10% for skill, and 20% for race restriction. How mush is the cost reduced? And can someone show me the math to find it?

Thanks,

Twice dead, Thriceborn

[Dragon Mage]

This one is great. It explains all the cost reductions for magic items.

http://brilliantgameologists.com/boards/index.php?topic=7274.0

As far as the math it works like this.

Total Value = starting cost * .75(this is the reduction for the feat).
Just do this for each reduction.

[Kelb_Panthera]

I think the OP is asking how to calculate the percentages, rather than how to get the lowest possible costs (which are spitting distance from free, btw).

It's actually really simple. All you have to do is remember the transitive* principle of multiplication; no matter the order, multiplying several numbers together always results in the same value.

you'd multiply the base cost like so: Base cost X .5 (for crafting) X .75 (for 25% off) X .7(for 30% off on racial restriction) X .9(for 10% off on skill restriction) = base cost X 0.23625. That's just shy of 24% of the base cost.

Do note that this is a big reason why many DM's won't allow a player to craft items with skill and race restrictions.