Yes. Weigh the cheese in lbs, measure it's height in inches, and multiply the two together Brine for that many hours in a saturated brine solution. For less than saturated (around 26.5% salt), you scale by 26.5/X where X is your percentage of salt.
To calculate your salt percentage, it's weight of salt/weight of solution. So, if you add 18g of salt to 100g of water, then you have 18/118 = 15.25% solution, and 1 part salt to 5 parts water (in weight) means 1/6, or 16.67% solution.
As an aside, I find the easiest way to make a 3% solution for washing, is to just weigh out 97g of water then add enough salt to increase the weight to 100g. That will last for awhile if you just washing a cheese or two.