Can someone explain to me the cost involved in improving magic items

[King Atticus]

The MIC (pg 233) talks about improving existing magic items but I'm having trouble wrapping my head around it and was hoping someone could help me learn to run the numbers. I get the weapon and armor advancement as well as the chart of common effects but not the cost involved in adding other spell effects.

For example:

If I have BOOTS OF AGILE LEAPING [Price (Item Level): 600 gp (3rd), Body Slot: Feet] and wanted to add the Accelerated Movement spell (sorcerer/wizard 1; SpC pg 7) as a property to these boots what would it cost?

What if I wanted to add additional spells to the same boots?

Understanding the numbers involved in item creation has always eluded me so I turn to you the sages of the playground. Thanks in advance for any help you can give me.

[Frog Dragon]

Generally, the price for creating a magic item is one half the price of the item. It also costs xp equal to 1/25 the item's price.

Adding a quality to the item, according to the magic item compendium, raises the price of the additional quality by a multiplier of 1.5.

Use activated or continuous lvl 1 spells cost an amount of gp equal to spell level times caster level times 2000gp.

So adding a Cl 1, lvl 1 spell as a continuous effect would cost you 1500gp and 120xp. Of course, in this case, it would actually be cheaper to add Agile Leaping to your Accelerated Movement rather than the other way around.

Also, correct me if I'm wrong on the XP. I'm not entirely sure if the xp cost is applied before or after the 1.5 multiplier. If it is before the multiplier, the cost is instead 80xp.

[Talakeal]

Quick question, have there ever been any official rules for upgrading the premade magic items? For example, improving a suit of Celestial Armor to +5 or adding the keen property to the Holy Avenger?

[Diarmuid]

A continuous effect based on a spell whose duration is expressed in rounds (such as Accelerated Movement) has its price multiplied by 4.

So adding "all the time" Accelerated Movement to those existing boots would cost you 12,000 gp to have someone else do it, or 6,000gp and 480xp if you did it yourself.

@Tala - short answer = no. Unless you can reverse engineer the item so it fits in with the item creation guidelines properly, then you wouldnt be able to determine what "plus" it currently is, to then be able to determine the price of the new "plus" and calculate the difference.

[Suddo]

Unfortunately I've heard two ways of doing this.
Either:
A) You just slap it on as though you had 2 boots. In which case It costs 12k, assuming your DM is cool with it having it have slot affinity which is reasonable.
B) The other is that you have to equivalent caster level across all effect which changes the cost to be 60k to add it at which point you should just put it on a slotless item.

Math:
For option A its 1 (CL) * 1 (Spell Level) * 2000 * 4 (due to duration) * 1.5 (second effect).
Option B increases the CL to 5 so its the same as the original.
Source:
http://www.d20srd.org/srd/magicItems/creatingMagicItems.htm

Edit: This all assumes that your DM will allow you to simply add effects to an existing item which is quite reasonable.

[Diarmuid]

Good point Suddo, I hadnt taken into consideration the CL for the existing magic effect, though I'm not 100% sure if it's required to have the same CL for all effects.

[Andorax]

Quick question, have there ever been any official rules for upgrading the premade magic items? For example, improving a suit of Celestial Armor to +5 or adding the keen property to the Holy Avenger?

There aren't official rules, but there is a solid guideline you can use.


Take your Celestial Armor example. It's +3 Chainmail "Plus some stuff". It costs 22,400 GP.

The cost for +3 Chainmail is 9,300 GP. So the other "stuff" is 13100.

One could make a case for +5 Celestial Armor being 16,000 more expensive (the difference between +3 Chain and +5 Chain).


The tricky part is whether, in your DM's opinion, the other "stuff" is all "added flat cost" stuff or if some of it is "added plus cost" stuff.

[Talakeal]

Yeah, that is what I always did. The problem was I always felt like I was cheating for doing so, especially when I couldn't tell if the extra cost was a + or a flat amount, and how much went to which property. I was hoping one of the later books published after I stopped playing might have some official rules.

[GoatBoy]

If it's just improved an existing quality, then I believe it's just the cost of the new item minus the cost of the existing item.

For example, improving a ring of protection +3 (18,000 to buy, 9,000 to make) to a ring of protection +5 (50,000 to buy, 25,000 to make) would have a market cost of 32,000 (16,000 to make).

[Diarmuid]

GB, that's the case for something simple like a +1 weapon to a +2 weapon (or your example).

But for the examples given (celestial armor) there are some unknown variables where assigning flat values for the extras or "plus" values is open to interpretation and taking it one way or the other vastly changes the price differences as discussed above.