TruePartCost and the machine-shop spreadsheet reckoning

Field notes

The site separates practical capacity from hours actually sold, arguing that charging all fixed costs to the hours sold can create a self-reinforcing pricing spiral. Its worked example describes a machine running at 20% capacity as appearing five times more expensive when its idle capacity is folded into the rate. The free calculator asks for a shop’s own costs, usable hours, and current charge rather than substituting an example business.