Inventory Reorder Cost Calculator

What the formula says

Reorder cost, or ordering cost, is what it costs to place and receive one order regardless of its size: total annual procurement cost ÷ orders placed. It is one of the two inputs to economic order quantity and the one most often guessed.

The components are buyer time, purchase order processing, supplier communication, any fixed freight or handling charge, goods-in labour, quality inspection, and the accounting work of matching and paying the invoice.

The numbers, worked through

A buyer spending 45 minutes per order at a fully-loaded $38 an hour is $28.50. Goods-in receiving and putaway at 30 minutes and $26 an hour is $13. Inspection $8. Accounts payable processing $12. Fixed documentation and handling charges $23.50.

Total $85 per order, which is the figure used throughout this cluster.

Across 7.4 orders a year on this product, that is $629 of ordering cost, very close to the $630 of carrying cost, as EOQ theory predicts at the optimum. Placing orders monthly instead would cost $1,020 and save $260 in carrying, a net loss of $131.

What the number leaves out

Much of it is staff time that is being paid regardless, which tempts businesses to treat it as zero. That is right at the margin for one extra order and wrong across a year: if order volume doubles, another person is eventually needed, and the cost is real at that scale.

It also varies enormously by order type. A repeat order to a known domestic supplier might cost $30; a first order from a new overseas supplier with samples, inspection and customs documentation can be several hundred, and averaging the two describes neither.

Turning it into a decision

Estimate it once, honestly, and use it. The flat EOQ cost curve means an estimate within 30% is entirely adequate, and having no figure at all means order quantities are set by habit.

Then look at what could be automated. Ordering cost is one of the few EOQ inputs a business can genuinely reduce, and every dollar removed lowers the economic order quantity and therefore the stock held.

Reducing it is worth more than optimising around it

Because EOQ scales with the square root of ordering cost, halving that cost reduces the economic order quantity by 29%, and cycle stock with it. On this product, moving from $85 to $42 an order takes EOQ from 280 to 198 and releases $738 of capital permanently.

The routes are mostly unglamorous: supplier portals or EDI instead of email, standing orders for predictable lines, consolidating multiple products into one purchase order, and three-way matching automated rather than manual.

This is the input worth attacking because it compounds. Lower ordering cost means more frequent orders, which means less cycle stock, which means less capital and less space, and unlike a service level decision, none of it costs anything in availability. It is one of the few genuinely free improvements available in inventory management.

One caution when estimating it: exclude any cost that varies with order size. Inbound freight charged per unit or per pallet belongs in the unit cost, not in the ordering cost, and including it inflates the EOQ in a way that produces systematically larger orders than the economics justify.

The test is simple, if the cost would be the same for an order of one unit and an order of a thousand, it belongs here. If it scales, it belongs in the landed cost.