How do you figure how many centerpieces you will need when you don't know how many guests will be coming?

I'm sure it like the catering. Base it off how many people you are planning to invite. This is what I'm doing!

I wanted to have 2 extra. If I don't use them on the tables, I will put on the table with the guest book, or by the self service drinks.

We made sure to get the amount we would need if everyone comes. If we have extras we will find someplace to use them (cake table, gift table, food tables, DJ booth, etc).

I also made enough to cover if everyone came, and I figured if there was an extra it would get used somewhere.

I went off how many people I was inviting and how many people we were going to put per table. I ordered 10 centerpieces, and I will end up with two extras, so they will go on the bar and the gift table.

My florist also said he could just make 8 instead of 10 just make the 8 bigger.

I am also making mine and am making 12 and hopefully won't need anymore

First figure out how many people each table will seat, and then go off of how many people you plan to invite(it is a given that not all of the people you invite will come, but you HAVE to plan for how many you invite NOT how many you expect to show up!), say you invite 100 guests and each table seats 10 people, then you need 10 centerpieces for 10 tables considering you only have one centerpiece. My centerpiece consists of 3 mason jars for one table for example (I'm attaching a picture to give you a better idea), and I invite 100 people and each table seats 10 people each, then I will need 30 mason jars total.

I guess it's best to figure everyone is coming and make that many. I already have some special items that I want to use in the other areas, but I'm sure I will have enough to do the last few weeks before the wedding without having to crank out a couple more centerpieces lol! I suppose if I don't need them I can give them as gifts or something.

Thanks everyone

The weddingwire guest list has been great for this. It's allowed me to group people into A, B, and C list. A represnets the number I know for sure are coming, B are the maybes and C are the people who I think/know will not come. based on that I've been able to get a good guestimate of how much I will need.