Advice Needed: Planning ahead for war

[Pinstar]

I'm a builder at heart, but I must say: I DO like having a contenent all to my self. I have no problem with wiping out any and all civs that share my land mass.

My problem lies in planning for these wars. I normally wait until I have such an insanely overwealming force that the war is no contest...but seeing the no-contest tells me I could have attacked 20 turns earlier.

My question is this: If I can scout out my enemy cities and count the total number of defenders, is there a general formula to tell me how many units I'll need to take that empire on?

If they have X cities, I should bring about X artillery (I almost never attack pre-catapults)

If each city has an average of X defenders, Bring X artillery and Y attackers to take it down. (Assuming both attacker and defender have a proper mix of units)

If I am one tech level ahead of my enemy, I could get away with X fewer units.


I KNOW there is no way to say exactly how many units you need for a war. It is impossible to exactly account for the random number generator, and you don't know how many of what kind of units the enemy will build once the war starts... I just need a general idea.

Any suggestions?

 

[Wodan]

Generally you'll want exactly 4 siege units because that will knock down city defenses in 1 turn, no more (speaking of trebuchets, but others can use this rough rule too). In addition, I'd expect to "waste" one trebuchet attacking each city, doing collateral damage. (You'll often need to use more than 1, but some will live, some will die... it'll average out.)
So, # siege units required = X + 4.

Y attackers, yes, given the above. Your actual attackers should almost never die, if you use siege engines properly.

Probably, most likely, you are under-using siege units. Build less other units, and more siege units.

Wodan