So here is how you would do it: Projected sales = fixed exp (足ꯠ) divided by 1_ƖǑ% + 27ǔ% + 12ǔ% + 25% (your new profit margin) = 造같 (new sales) You can do this for as many years out as you want. Obviously this is based on your first year's fixed expenses remaining constant and no consideration of depreciation, inflation, or taxes. But most likely you would need to increase your fixed expenses because you're going to probably have more rent, utilities, or such as your business grows. So, you would simple put in your new fixed expense number in place of the existing one for each of the years you would be planning for. So, you see if you decided you wanted a 35% profit margin at year 5 then you could see how much sales it would take to give you that. Now it's also important to know how many more customers you would need as well so you should always look at that unless you have another way of growing your sales other than with new customers.
But do not be too paranoid, make sure you are showing it to people you trust, whose feedback you welcome and can be genuinely useful in guiding how the plan takes shape. Very often when working as individuals we get very close to certain details and miss out a big thing that has slipped your mind. You can concentrate so much on essential financials and supply logistics, but overlook other issues like marketing or opening times. By showing the plan to someone you trust, they can have a look and see what might be missing or worth developing more. Getting that valuable second opinion on how robust your idea is will put you in a much better position to start and keep going successfully.