This normally depends on your preference and needs. However, the most popular size of the canvas is 16″ X20″. We also recommend you to use around 500-1000 pixels canvas. This size is just perfect for those easy little paintings where you do not care about the final result. However, try and go for 2000-5000 pixels if you might like to print stuff or if you wish to turn them into a proper painting. You can always choose bigger than what you have visualised in your mind, so there are no limitations you feel while imprinting your mind on the canvas. Hope the suggestion helps, and you never have to feel discouraged due to a lack of space!