Raid size: how it works and the numbers

Short answer

A village can only be attacked by so many zombies from one attacker at a time: 12 at the weakest bands, up to 120 at the strongest.

What it does

To keep big hordes from bullying small villages, one attacker can have at most a set number of zombies marching at a village at once. The limit comes from the village being attacked: its strength band decides it, from 12 for the lowest band to 120 for the highest.

It counts every one of your marches to that village that hasn't been fought yet. If the next march would go over, it's refused with a message like “Hollow Orchard takes at most 24 attackers”. Send a smaller squad, or wait for the first one to arrive.

If you send a raid without choosing a count, it is trimmed to the room the cap has left rather than refused.

The Horde King is the exception: it has no cap.

Raid size by band

Village strength band	Village strength	Most attackers from one village
1	0+	12
2	120+	18
3	250+	24
4	400+	30
5	550+	45
6	750+	60
7	950+	75
8	1,150+	90
9	1,400+	105
10	1,700+	120

Tips

Check the cap on the target sheet before you pick squads: sending fewer, stronger zombies is often the better raid anyway.
As a defender, a higher strength band means a bigger cap: growing also means facing bigger raids.

Questions

Why was my raid refused for being too big?

A village takes at most 12 to 120 attackers from you at once, depending on its strength band. The total includes marches you already have on the way to it. Send fewer zombies, or wait.

Numbers come straight from the game's rules and update with every release.