Change in NWC formula to calculate the change in net working capital based on the beginning and ending NWC. The change in net working capital formula is given as N = E - B, where 'E' is ending net working capital and 'B' is beginning NWC. The Working capital is the difference between a company's current assets and current liabilities. Calculating the change in NWC helps in finding out the ability of company to utilize assets in an efficient manner.