You need at least 5 clan members to participate in Clan Capital activities, since a clan must have enough players to take part in Raid Weekend and contribute attacks. Supercell also notes that up to 50 players can participate in Raid Weekend.

Quick answer

  • Minimum: 5 members.
  • Maximum in Raid Weekend: 50 members.

Practical note

In practice, clans can still build and progress in Clan Capital with fewer than 50 members, but having more active players makes raids and upgrades go much faster. A lot of players aim for a fuller clan so they can get more Capital contributions each weekend.

One-line version

For Clan Capital, the useful number to remember is 5 minimum, 50 maximum for Raid Weekend.