Rabadon's Vs Void Staff Math

Altonius Amakiir·Mar 1, 2018·10 votes·4,843 views

Made a couple excel spreadsheets to calculate when Void Staff is better than Rabadon's and vice versa. Here is a group of tables that makes it fairly easy to understand:

https://1drv.ms/x/s!Ah4pdH2v9szDgtBgmCD7CgOnLqhQPg

There are multiple sheets for each MR, 900 MR=90% DR, 400 MR=80% DR, and so forth.

Here is the data tables I used to get the information:

Scenarios where Rabadon's Deathcap is better: https://1drv.ms/x/s!Ah4pdH2v9szDgtBE549dmwSKFDak_w

Scenarios where Void Staff is better: https://1drv.ms/x/s!Ah4pdH2v9szDgtBcf_622wkUdDzoTg

Maths/equations: https://1drv.ms/x/s!Ah4pdH2v9szDgtBePyBCycIegIyTgw

And here is how I got the equations:

https://imgur.com/a/gTDuZ

P.S. All these weird looking links are just OneDrive links (a cloud service).

10 Comments

GrReaper96Mar 2, 20184 votes

Can someone give a general TLDR answer for this?

Altonius AmakiirMar 2, 20181 votes

That would be the first link. It can't be simplified much more than that.

Choose the sheet for the corresponding MR of your opponent (43 for squishy, 67 or 100 if they built some MR to counter you; 233.33 for tanks, 150 for fighters, 400 for someone only building MR; 25 MR or less if you have flat pen)

Then look at the at the average AP ratio for your champ and average base damage on abilities (doesn't have to be perfect if you want to make this quick) and find the corresponding cell.

Example 1: Zilean has a 90% AP ratio, 300 base damage. Usual targets are squishies and fighters. So I look at 67 MR as an average, the cell for those numbers is purple. Thus always get Rabadon's, not Void.

Example 2: Veigar has about an average of 70% AP ratio for his abilities and about 275 base. Usual targets are non-tanks. I also build flat pen on him. So I look at 100 MR and 11 MR to see both extremes of my target range, accounting for pen. Both are in purple, so Rabadon's.

Example 3: Ahri has about an average of 55% AP ratio for her abilities (if you average out times where you don't get full damage) and about a 250 base average. Pen is also stacked on her and her targets are generally only squishies. So I look at 25 MR, and 100 MR (just to see what happens if she has to fight a fighter). For 25 MR she is in the purple, so if the enemy is mostly squish (non-fighters/tanks with 1 MR item or less) then go Rabadon's. For 100 MR she falls between Void and Rabadon's territory, so in all likeliness it's still better to build Rabadon's, but if they have 2 or 3 people stacking MR, Void would become a good choice.

vgamedudeMar 1, 20181 votes

so almost always deathcap unless they have people who are tanky? AKA no void against banshee veil only?

Altonius AmakiirMar 2, 20184 votes

Well, let's assume a level 11 Veigar with Banshee's Veil is your intended target. 34.4 base MR + 60 MR = 94.4 MR. Places us at about 100 MR. So we go to that table. If you have 200 base magic damage and a 30% AP ratio or less, 300 base magic damage and a 50% AP ratio or less, or 400 base magic damage with an AP ratio of 70% or less; then get Void (orange means Rabadon's is still good, but Void gives an earlier power spike). Otherwise get Rabadon's. It depends a lot on your champion's kit and who your ideal target will be.

vgamedudeMar 2, 20181 votes

Damn I don't know any of the ratios or bases on champs I play lmao

EkyonKunMar 2, 20183 votes

Hmm DCap vs Void Staff is a little tricky when it comes to which you should get first (If you want burst, I'd recommend getting both) but almost always Void Staff first unless you're snowballing so hard it's silly, AND they happen to be building no MR at all.

The OP is not wrong in which will do more damage as an inventory slot, but something to take into account is the downtime of building a DCap vs. finishing a Void Staff. Since you'll finish Void sooner, you get your powerspike sooner. In the time it takes you to finish item 1058 to work on your DCap, you'll already be 150 gold away from having the 70 AP + 40% Pen from just having Void Staff by itself. Also, since you can't just build a item 1026 item 1052 and then choose which you want later anymore, you HAVE to commit to one or the other.

So unless your AP ratios are just THAT amazingly high AND the enemy is building literally zero MR, Void Staff is better to build first. Unless you just so happen to have 3600 gold to blow. In which case, you probably should have just backed earlier.

AirKingNeoMar 2, 20181 votes

What about the effective gold efficiency of each item?

Altonius AmakiirMar 2, 20181 votes

I'm not going into that, all I'm doing is calculating slot efficiency. You will have to adjust on your own terms for gold efficiency. Please note however that the blue and orange sections are the only ones where the slot efficiency comes close. So that is probably the only places where gold efficiency matters.

wildfox99Mar 2, 20181 votes

[{quoted}](name=Altonius Amakiir,realm=NA,application-id=3ErqAdtq,discussion-id=tZiHxOX4,comment-id=,timestamp=2018-03-01T22:59:52.514+0000)

Made a couple excel spreadsheets to calculate when Void Staff is better than Rabadon's and vice versa. Here is a group of tables that makes it fairly easy to understand:

https://1drv.ms/x/s!Ah4pdH2v9szDgtBgmCD7CgOnLqhQPg

There are multiple sheets for each MR, 900 MR=90% DR, 400 MR=80% DR, and so forth.

Here is the data tables I used to get the information:

Scenarios where Rabadon's Deathcap is better: https://1drv.ms/x/s!Ah4pdH2v9szDgtBE549dmwSKFDak_w

Scenarios where Void Staff is better: https://1drv.ms/x/s!Ah4pdH2v9szDgtBcf_622wkUdDzoTg

Maths/equations: https://1drv.ms/x/s!Ah4pdH2v9szDgtBePyBCycIegIyTgw

And here is how I got the equations:

https://imgur.com/a/gTDuZ

P.S. All these weird looking links are just OneDrive links (a cloud service).