What is FIFO inventory costing?
FIFO (First-In, First-Out) is an inventory valuation method that assumes the oldest units in stock are sold first. It’s one of the most common methods for calculating Cost of Goods Sold (COGS) and ending inventory value.
How this calculator works
Enter up to three purchase batches (quantity and cost per unit, oldest first) and how many units were sold. The calculator uses up the oldest batch first, then moves to the next, to determine COGS. Whatever units remain make up the ending inventory value.
This is a simplified educational model; real inventory systems may track many more batches and additional costs such as freight.
Last reviewed August 2026