This is a quick summary for choosing canvas size. I prefer to stick to one size and then enlarge it when I need. Soon I find out that some of the canvas sizes are related to each other. So I want to put them together to have a clear view that which size comes from which. It is always easier to start with a small size and then enlarge it.
S”=size in inch
Note: these are just some common sizes that I usually find in store. Of course you can always customize when you need to.
I like to start with 8 × 10”, and then enlarge it to 16 × 20″ and 24 × 30″. If I want to painting a 18 × 24” canvas I would start my sketch on 6 × 8” or 9 × 12”. Nothing special, just the smaller size gives you more control in terms of whole composition and color theme, I think. ^_^
I hope you would find this helpful.