Free inventory calculators

Calculate average inventory from a beginning and ending balance or from monthly balances, then inventory turnover and days of inventory from cost of goods sold. Free, no sign-up.

Calculate supplier lead time from purchase order history: mean, sample standard deviation, slip against a quote, and expected arrival date. Free, no sign-up.

Calculate min and max inventory levels from demand, lead time and safety stock, and see the order-up-to quantity against your current inventory position. Free.

Calculate par level from daily usage, days between deliveries, lead time and a buffer, then see how much to order against what is on hand. Free, no sign-up.

Calculate safety stock and reorder point from demand variability, lead-time variability and a target cycle service level. Free, no sign-up.

Calculate weeks of supply and days of supply from on-hand units and average weekly sales, with a projected run-out date and excess vs a target. Free, no sign-up.

Allocate freight, insurance, duty and brokerage across a shipment's line items to get a true landed unit cost. Free, no sign-up, no tariff data shipped.

Calculate retail open to buy from planned sales, markdowns, planned end-of-month stock, beginning stock and stock on order, at retail and at cost. Month by month, free, no sign-up.

Calculate MAPE, WAPE, forecast accuracy and bias from actual vs forecast periods, with zero-actual periods handled explicitly. Free, no sign-up.

Calculate gross profit, margin % and markup % from cost and price, or solve for the price a target margin needs. Free margin vs markup calculator, no sign-up.

Calculate session-based ecommerce conversion rate, revenue per session and the orders and revenue a target rate would add. Free, no sign-up.

Roll a single-level bill of materials up into a unit and batch cost, with scrap, labour, overhead and both scrap conventions named. Free, no sign-up.