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Hey all

Does anyone know of an app or has made a spreadsheet that lets you calculate how many shots of X weapon it will take to kill Y unit?

I know the web version of mathhammer shows 'shots required to have a 50% chance of killing the target', but I am more interested on the actual number of shots (i.e. 100%) if that makes sense.

TIA

There is no number of shots that guarantees a kill, because nothing prevents you from rolling 1s to hit forever. Even hit on 2+ with a reroll is still 1/36 to miss and never even get to the to-wound or armor save rolls.

There's no number that will result in 100% chance-you can always miss, or fail to wound, or they make their save or FNP.

I use Anydice for my mathammer, as well as math.

Phenatix wrote:
There is no number of shots that guarantees a kill, because nothing prevents you from rolling 1s to hit forever. Even hit on 2+ with a reroll is still 1/36 to miss and never even get to the to-wound or armor save rolls.

I understand that. Let me re-phrase it, a site or app that lets you determine the *average* number of shots required to kill a unit, not the average number of shots to give a 50% chance to kill it.


Automatically Appended Next Post:

 JNAProductions wrote:
There's no number that will result in 100% chance-you can always miss, or fail to wound, or they make their save or FNP.

I use Anydice for my mathammer, as well as math.

Thanks, I will check that out.

 XeonDragon wrote:

Phenatix wrote:
There is no number of shots that guarantees a kill, because nothing prevents you from rolling 1s to hit forever. Even hit on 2+ with a reroll is still 1/36 to miss and never even get to the to-wound or armor save rolls.

I understand that. Let me re-phrase it, a site or app that lets you determine the *average* number of shots required to kill a unit, not the average number of shots to give a 50% chance to kill it.


Automatically Appended Next Post:

 JNAProductions wrote:
There's no number that will result in 100% chance-you can always miss, or fail to wound, or they make their save or FNP.

I use Anydice for my mathammer, as well as math.

Thanks, I will check that out.

So you really have to pick the chance you want to look at. You’re going to have different answers for shots to 50%, 90%, 95%, 99% kill etc.

From there you can either do simple math for the simple cases (no rerolls, rend etc) or a Monte Carlo approach is very easy to model and you can capture the full process.

Good point. Is there a percentage that you would suggest? 50% - what mathhammers uses - seems a bit iffy to me. I'm aiming for something that - as much as is possible when dealing with random numbers - reflects, on average, a degree of reliability, if that makes sense. What would you suggest, 60%, 85%?

https://www.reddit.com/r/Necrontyr/comments/9o905g/necron_unit_efficiency_dashboardvisualizer_for/

I think this is what you are looking for. You'll have to work a bit to make the spreadsheet work for you, I think doing it manually one unit at a time would be easier unless you are looking to calculate over 40 units against 6+ different weapons. It isn't worth it to spend 6 hours building an automated farm in Minecraft on a single player world if you could have manually made enough resources during those 6 hours to last the lifetime of the world.

You can absolutely calculate what it will take on average to kill a unit, that number of hits might only kill the target 50% of the time, the other 50% of the time it will take more or less hits, but knowing the average is still valuable.

Thanks, that looks very useful

http://www.dice-hammer.com/ is the site I use.

Thanks!

The web version of the 'Mathhammer' app does not show the number of shots needed to achieve a 50% chance of killing the target; it shows the average number of shots to kill the target.

The difference between the two is tricky and gets into distribution curves, and they each have their own application, but if you want to know the average number of shots to kill a unit, the Mathhammer app or just doing the calculation yourself is the way to go.

For example: Let's say you have a trial that will succeed on a 6 on a D6. Very simple. How many dice do you need to roll to expect at least one 6?

1 success / 0.1666 success chance = 6 average. You roll six dice, you average a single 6. This is the easy and useful calculation.

But what's the actual chance of succeeding with six dice? You can calculate that by determining the chance of none of the dice rolling 6, which is .8333^6 , which comes to 33%. That means you have a 67% chance of at least 1 die showing a 6.

To get a 50% chance of rolling at least one six, you need to roll four dice. .83333^4 = 0.48, giving a 52% chance of at least one six.

And if you want a 90% chance of rolling at least one six, you need to roll thirteen dice. .83333^13 = .093, giving just over a 90% chance of at least one six.

Bottom line: Unless you really enjoy doing logarithms, stick to average results, and the Mathhammer app will be sufficient.


Automatically Appended Next Post:
To be clear, if you're using this particular website, it's dead wrong in its 'Shots required to have a 50% chance of killing the target' calculation.

The programmer appears to have just taken the number of shots required to average one kill, and divided it in two. That is not statistically accurate at all.

I would just ignore that part of it entirely and focus on averages.

Edit: Messing around with it further, I have no idea how the 50% chance numbers are being calculated, but it's way off- it's claiming 42 lasgun shots has a 50% chance of killing a Knight. Just stick to averages, and understand that when average damage = target's wounds, the likelihood will be in the 60-80% range.

Thanks, that was very useful