How many dwarfs do I need for a raid.

[ʍolɟ ǝɥʇ ǝsɹǝʌǝɹ]

I have like 50 military dwarfs, but all the enemy cities are ~70 to ~100. How many do I need to send to succeed.

[Fel]

Usually you don't need more than 3 squads.
What really matters is their skills and equipment.

[ʍolɟ ǝɥʇ ǝsɹǝʌǝɹ]

Thanks. I have full sets of iron and proficient weapon masteries

[Fel]

Iron is not that great but it should do, "proficient" is only level 5 so it's not that good.
It could work but you will most likely lose some dwarves.

The population shown only account for the main population of that site, so animals and monsters are not counted but they could appear in the fight.
Goblins and elves in particular can have some fairly dangerous animals defending their settlements.

[Barón Fendetestas]

I'm in the process of destroying a goblin civilization. I'm using 10 legendary dwarves with good health statistics and equipped with steel armor and weapons. They can 1v1 a forgotten beast

[RadCon One]

For reference: I sent 6 starter dwarves with copper armor, shields, and axes, along with 10 points in military skills, to raid a 50 or so goblin settlement the moment I embarked (just to try it out) and they won and came back with supplies later (I don't remember how many they actually killed, it definitely wasn't a total wipe).

It was a fun little experiment that is easy to test yourself if you want: Just do a 1x1 embark as close as you can to another relatively small settlement with the supplies you brought being military equipment and your dwarves skills being in the military trees and try it for yourself.

[ʍolɟ ǝɥʇ ǝsɹǝʌǝɹ]

I have a squad of 2 legendary sword dwarf 1 legendary mace dwarf and a hammer lord. Think I'm off to a good start

[Fel]

Swords and mace are somewhat weird choices but yeah.

Now if each legendary is set to lead their own squad (enforcing the weapon for other members to be the same as well) you'll get plenty of good fighters fairly quickly thanks to the teaching skill.

[ʍolɟ ǝɥʇ ǝsɹǝʌǝɹ]

it was the individual preference. Why is it weird??

[Fel]

Well, a mace is a weaker version of a warhammer.
Swords can in theory do all 3 types of damage but it does all much worse than the specialized counterpart (axes for cutting, spears for piercing and warhammers for blunt).

Both are somewhat decent against weaker enemies, especially unarmored or lightly armored, but they scale badly with enemies that have either size or armor (or both).

Basically it's decent enough for goblins but you'll have troubles with bigger enemies including megabeasts and forgotten beasts.