Daves Garden has a plant file that you can look up your peppers on and it tells you how big they grow,how far to space them and how big the plant can get.
That should help you find out what you need to have container wise.

You may have to sign up to use the Plant files.click on Guides and information.

Here is a link that might be useful: plant files

I have found that depending on your soil/soiless type, nutrient availability, etc. you can get by with as small as 1 gallon containers. The containers will control rootmass, and therefor to some extant, control plant size as well. I don't put much stock into what some folks say about how big a plant can get. Last year I had habaneros that were 6 foot square massive producers, in 12 gallon containers, and jalapenos that were 4.5 foot square. One serrano was over 8 feet tall, though it was trained somewhat to run along the fence on a slope. It's all fun though!! Good luck!!
TiMo

I grow most of mine in 12" pots and some of the smaller ones in 10" pots. One consideration with smaller pots is more frequent watering.

I've got about 24-12 inch pots and 6-14 inch pots. I am planning to expand to about 50 pots this year. I am planning to just buy 14 inch pots for the watering issue. I have not been able to grow any huge plants so far. Maybe I've been too careful with the fertilizer, but 12 inch pots have seemed sufficient for me. I probably need to get more experience to make the pepper plants grow optimally.

I got a bunch of round pots today at the $.99 store that are 14 in X 11 in. deep.They came in green,gray and a redish brown.
Tried them last year to see if they were junk or not.
They do get a little bit brittle from the sun but still flex.Probably good for 2-3 seasons depending on how you treat them.I put a shovel through one.
For 99 cents you can't complain if you have to replace a few though every couple years.
The ones that got brittle were dayglow green and a different kind of plastic.They started to break after only a couple weeks in the sun.

Their clay pots are really thin but they are about 8 x 10 deep give or take.
They have some 14 X 6.5 ones too that are plastic.

Problem with clay pots is that they dry out much faster than plastic pots

I put small plants in clay ones and clog up most of the drain hole.
I also put them between the plastic pots so they don't get much sun on them.
They still dry out more than plastic ones.
Being thin they probably dry out faster than thicker ones-less clay to hold the water the clay sucks up.
If they weren't so cheep and thin I'd seal the insides but it's not worth messing with them.
I know people who like clay pots so I mentioned that they were there too.

The 14 X 11 ones are good for some of the smaller peppers I think.
I wish they were deeper though so a 24-36 in. plant wouldn't tip over ot pull out in the wind.
They seem to be good for my orange thai and the red hot thai plants,
I'm putting some ornamentals in them too.
I don't move them much except to turn them around in the sun every so often so.

thanks all for your response !

your providing some much needed advice for future steps in my pepper project.

found good info in daves garden plant files.

thanks again
wildlifeman