Will your 100 watt marshall guitar amp be loud enough for a gig?

It depends on the size of the venue and the number of people in the audience. A 100 watt Marshall guitar amp can be loud enough for a small club or bar, but it might not be loud enough for a large concert hall or outdoor festival. If you're unsure if your amp will be loud enough, it's always a good idea to bring a backup amp or PA system.