+ Item Drop % Needed to Guarantee a Drop

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Turtle Juice
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+ Item Drop % Needed to Guarantee a Drop

Post by Turtle Juice » Wed Jun 30, 2010 11:53 am

I run into this problem with every run (partially because my math skills are limited) - but I'm constantly asking in chat what + item drop percent I need to guarantee an item to drop, and I thought it would be great to have a little guide to refer to.

So, here is a list of what I'm trying to find the + item percent needed to guarantee a drop, feel free to add items and please either add the + percent needed, or let me know what the formula is and I can use my calculating device to figure it out.

Main items needed
Okay - I added in the % needed to guarantee a drop, but rounded (so if it is 18% I rounded up to 20%, etc.)

Sonar-in-a-biscuit (crazy range here) 18.6% - 30.2% range
+ 400% (crazy) ... 233.33% needed at + 30% drop rate

White pixel (from Blooper) 60, 70, & 80% - so assume 60% drop rate for all 3
+ 66.66%

Tattered scrap of paper 29.9% drop rate
+ 233.33%

disintegrating quill pen 21.2% drop rate
+ 400%

inkwell 30% drop rate
+ 233.33%

Glass of goat's milk 20.4% drop rate
+ 400%

Goat cheese 39.2% drop rate
+ 150%

Drum machine 29.5% drop rate
+ 233.33%

Tomb ratchet 20% drop rate
+ 400%

Heavy D 39.3% drop rate
+ 150%

soft green echo eyedrop antidote 21.2% (Random encounter) 30.8% (Quiet healer)
+ 400% (low end) and 233.33% (high end)

Ruby W, Metallic A, Lowercase n 30% drop rate
+ 233.33%

Sunken eyes & broken wings 50% drop rate
+ 100% (why can't they all be this easy?)

Stunt nuts 31.9% & 29.3% drop rate
+ 233.33%

Thin black candle 29.2% drop rate
+ 233.33%

Ketchup hound 36.3% drop rate
+ 185.71%

Rigging shampoo, ball polish, mizzenmast mop 30% drop rate
+ 233.33%

Dusty bottle 19% - 21.1% drop rate
+ 400%


Here are others for tower, HC needs, backfarming, etc.:


Stars / lines 22.6% - 40% range
+ 400% to 150%

Knob Goblin harem pants 3.7%
too low to calculate (like + 2,600%)

Knob Goblin harem veil 4.4%
+ a ton that of gear and potions you don't have

Knob Goblin perfume 14.7%
+ 566.66%

Hellion cube 29.7%
+ 400%

Giant needle 28.4%
+ 400%

Furry fur 37.4%
+ 185.71% (rounded down)

Awful poetry journal 29%
+ 233.33%

bird rib and lion oil 20%
+ 400%

wussiness potion 30%
+ 233.33%

pygmy blowgun 30%
+ 233.33%

pygmy pygment 25.4%
+ 300%

jungle drum 10.1%
+ 900%

canopic jar 30%
+ 233.33%

bronzed locust 19.3%
+ 400%

More to come.


Maybe the easiest thing to help would be a simple list of percent drop by 10s with % modifier needed to get it to 100.

Any other thoughts would be helpful.

Thanks.
TJ
Last edited by Turtle Juice on Tue Jul 20, 2010 3:20 pm, edited 3 times in total.

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NardoLoopa
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Re: + Item Drop % Needed to Guarantee a Drop

Post by NardoLoopa » Wed Jun 30, 2010 11:55 am

I could be wrong, but I believe Mafia tells you what your adjusted drop-rate is in the Locations panel for whatever your "+drops" is at the time.

The adjusted drop-rate is: base_drop*(1+bonus/ 100)
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stupac2
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Re: + Item Drop % Needed to Guarantee a Drop

Post by stupac2 » Wed Jun 30, 2010 12:20 pm

If you know the base rate calculating what you need is pretty straightforward. It's just (100/rate - 1)*100

So for tomb ratchets, which are a 20% rate, you need 400% items (100/20 = 5, 5-1 = 4, 4*100 = 400). In a case like the bats where it's variable across monsters, calculate based on the lowest (not that it matters there, since you're not going to max out a 30% rate that early in a run anyway).

Also, as nardo says mafia tells you the modified rates in the Location Details drop-down on the main tab. Very useful for those times you're not sure what the rate is.

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Re: + Item Drop % Needed to Guarantee a Drop

Post by maddsurgeon » Wed Jun 30, 2010 12:39 pm

Perhaps the best format for this information would be a spreadsheet that runs all the relevant items through the formula?

It would be a one-glance thing where you'd just need to plug in your item rate, and would obviate the need to calculate each time.
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Turtle Juice
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Re: + Item Drop % Needed to Guarantee a Drop

Post by Turtle Juice » Wed Jun 30, 2010 1:26 pm

Okay, so following that sweet formula - here are the drop rates % needed to ensure drops in increments of 5%:

5% rate, you need +1,900%
10% rate, you need +900%
15% rate, you need +566.66%
20% rate, you need +400%
25% rate, you need +300%
30% rate, you need +233.33%
35% rate, you need +185.71%0
40% rate, you need +150%
45% rate, you need +122.22%
50% rate, you need +100%
55% rate, you need +81.81%
60% rate, you need +66.66%
65% rate, you need +53.84%
70% rate, you need +42.85%
75% rate, you need +33.33%
80% rate, you need +25%
85% rate, you need +17.64%
90% rate, you need +11.11%
95% rate, you need +5.26%
100% rate, you need +0!

And I like having a little cheat sheet rather than going to mafia and adding + items until it gets up to 100 - but that's just me.

Kevlar
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Re: + Item Drop % Needed to Guarantee a Drop

Post by Kevlar » Wed Jun 30, 2010 3:15 pm

Sweet cheat sheet!

Could you perhaps highlight the items that cannot be yellow rayed? Cos those are the ones that really get on my nerves ;)
grrrrrrr

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Re: + Item Drop % Needed to Guarantee a Drop

Post by Omri » Wed Jun 30, 2010 5:32 pm


caprosmaster
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Re: + Item Drop % Needed to Guarantee a Drop

Post by caprosmaster » Sun Jul 18, 2010 12:22 pm

You've got goat cheese down as needing 185% to assure the drop, you only need 150% however to assure the drop

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Turtle Juice
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Re: + Item Drop % Needed to Guarantee a Drop

Post by Turtle Juice » Tue Jul 20, 2010 1:53 pm

Ooops, fixed Goat Cheese ...

39.2% drop rate ... 155.10% + items to guarantee 100% drop.

100/39.2 = 2.55 - 1 = 1.55 x 100 = 155.10

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Re: + Item Drop % Needed to Guarantee a Drop

Post by stupac2 » Tue Jul 20, 2010 1:59 pm

39.2 = 40.

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Turtle Juice
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Re: + Item Drop % Needed to Guarantee a Drop

Post by Turtle Juice » Tue Jul 20, 2010 3:21 pm

Geez, I feel like I'm in 6th grade math again ... 150% it is.

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stupac2
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Re: + Item Drop % Needed to Guarantee a Drop

Post by stupac2 » Tue Jul 20, 2010 3:43 pm

Turtle Juice wrote:Geez, I feel like I'm in 6th grade math again ... 150% it is.
One of the greatest things about the KoL-verse is that we can talk to its god and he likes multiples of 5. Jick would never code a 39.2% drop rate (and not to mention that if he did it would have to be a conditional, and so couldn't be PPed, but sonars can, etc).

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Re: + Item Drop % Needed to Guarantee a Drop

Post by Kelemvor » Tue Jul 20, 2010 3:51 pm

This implies that most of the drop rates on the wiki are incorrect, since they are not round multiples of 5.

I usually get around this by just mentally rounding down to the nearest multiple of 5 and calculating +item needed from there.

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NotJim
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Re: + Item Drop % Needed to Guarantee a Drop

Post by NotJim » Tue Jul 20, 2010 10:18 pm

Kelemvor wrote:This implies that most of the drop rates on the wiki are incorrect, since they are not round multiples of 5.
IIRC, most if not all of the drop rates are taken from Yiab's spading, who posts the exact values he gets from the massive amount of trials he runs through, not caring about rounding. Hence the odd values you'll get in the wiki, and not really 'incorrect'. :P

Also, a relevant note for those who don't notice it already: The sweet spot for 'readily available' +item is 233.33%. Why is this? Because a TON of important items have a 30% drop rate: tattered scraps, skullbat sonars, all of the important castle items, soft greens from healers, nearly all of the valley scrolls, f'c'le items, black no2/adder bladder/other gate items, drum machine, stars/lines... the list keeps going on. Anything at 35% is rare (only hound/stew items IIRC) and 40% is easy enough anyway.

As an aside, I don't think any items actually exist in the game that have 25% drop rate. O_o

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Re: + Item Drop % Needed to Guarantee a Drop

Post by lostcalpolydude » Tue Jul 20, 2010 11:15 pm

NotJim wrote:As an aside, I don't think any items actually exist in the game that have 25% drop rate. O_o
Mafia data files make this trivial to check.

http://kol.coldfront.net/thekolwiki/ind ... ahogany%29
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