Free inventory calculators

Calculate average inventory from beginning and ending inventory or monthly balances, then turnover and days of inventory from cost of goods sold. Free.

Days in inventory calculator: work out days inventory outstanding (DIO) from average inventory and cost of goods sold, with the formula and an example.

Find economic order quantity, annual ordering and holding costs, and the effect of a supplier minimum. Free EOQ calculator with a worked example.

Estimate cubic feet needed for your planned FBA cover, compare it with your Seller Central limit and current usage, and see what needs upstream storage.

Calculate annual inventory carrying cost from capital, storage, insurance, obsolescence and handling; see monthly and per-unit cost.

Convert an inventory cycle service level to a Z score, expected stockout cycles and safety stock, or work back from stock held.

Calculate the inventory turnover ratio from cost of goods sold and average inventory, and see how many days one turn takes. Formula and worked example.

Calculate supplier lead time from purchase order history: mean, sample standard deviation, slip against a quote and expected arrival date. Free.

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

Calculate units to order from demand through lead time and review period, safety stock, on-hand and on-order units, supplier minimum and case pack.

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

Calculate when to reorder from daily demand, supplier lead time and safety stock. See the formula, worked example and common mistakes.

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

Calculate sell-through rate from units sold, units received and optional opening stock over the same period, with a worked example and interpretation tips.

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.

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.

Open to buy calculator: plan monthly retail OTB from sales, markdowns, end-of-month stock, beginning stock and stock on order, at retail and at cost.

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

Calculate cash conversion cycle in days and estimate the cash tied up by one extra inventory or receivables day.

Calculate cost of goods sold from beginning inventory, purchases and ending inventory. Includes the manufacturing COGS formula and a worked example.

Calculate gross margin return on inventory from sales, cost of goods sold and average inventory at cost; compare with inventory turns.

Calculate gross profit, margin % and markup % from cost and price, or solve for the price a target margin needs. Free margin vs markup calculator.

Calculate selling price from cost and markup, or markup from selling price. Compare markup with profit margin and see a conversion table.

Work out your ecommerce conversion rate from sessions and orders in seconds, then get revenue per session and what a higher rate adds in orders and sales.

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.