At the crux of it - market sizing is about the units.

If you want to estimate sales - you factor the price

If you want to estimate costs - you factor the costs

That said - it would be good to provide some more context so that we can answer the question better. Currently the question is a bit vague/generic.

Hi,

This is a very general question, and it would definitely depend on the specific case. Generally speaking, cost would not be of utmost importance - you would think about sales price, geography, customer type, competition, etc. However, cost could be an influencing factor - for instance, perhaps your sales price needs to be set at a certain number to cover some unusually high production cost, which would limit your potential market. So I would say it is unusual, but I wouldn't take it off the table altogether. If there is a specific market sizing question you are thinking about, feel free to message me with more details and we can go through it.

Hi there,

Honestly, I'd never say never with market sizing! I suppose I could see a use or two for using cost in order to calculate price, though I haven't really seen a case yet where this applies!