It depends on the size of the venue, how many people will attend the party and what kind of atmosphere you want to create. Usually, 50 watts RMS is probably plenty at a home party. But if you want to really rock out outdoors, then you'll need more than 200 watts RMS. A good rule of thumb is that you'll need about 10 watts per person. So, for a party of 100 people, you'll need 1,000 watts (10 x 100). But keep in mind that this is just a general guideline. If you're looking to create a more energetic atmosphere, you may want to go with 20 watts per person. But if you're looking for a more relaxed atmosphere, you may only need 5 watts per person. If you're not sure, feel free to ask our customer service to help you figure out exactly what you need.