All companies who use LIFO method have to disclose the amount of LIFO reserve in its inventory notes accompanying financial report. LIFO reserve is defined as the difference between inventory balance under FIFO method and inventory balance under LIFO method. A company using LIFO must disclose LIFO reserve amount for both its beginning inventory balance and ending inventory balance. So, users of financial statements will know, had the company used FIFO, what the inventory balances would have been. They can also convert COGS LIFO to COGS FIFO, etc..