Sooner or later, no matter how obviously brilliant your idea, someone is going to ask "how big is it?" And in too many situations, this question will be asked way too early in the process (but that's a subject for another day). As a result, I'm even hesitant to provide folks here with a way to answer the question. Because providing a financial estimate too early in the process is more often a Kiss of Death than a useful bit of information. Why? Because if the topic under discussion is an incremental innovation, everyone probably already knows the answer (whatever 1-2% more of the existing sales would be). In the case of breakthrough innovations, the answer is a much more subjective question because there is no existing frame of reference for the answer. New ideas have new markets, new customers, new value propositions, new purchase behaviors, etc. So at best, providing financial information is a S.W.A.G. (Silly or Scientific Wild Ass Guess). Breakthrough innovation should be looked predominantly through a strategic lens in the early stages. Stay Loose until Rigor Counts!