Inventory in cases, pieces and kilos: test the conversions

Which unit should inventory retain?

Purchasing, warehousing and sales can use different units. Trouble starts when “two cases” reaches a report without identifying the product, how many pieces each case holds or which pack version arrived. Choose a stable base unit and also show the quantity the person entered. This lets you review a delivery document without having to reconstruct the conversion in your head.

Odoo 19 documents an inventory unit and purchase units converted on warehouse documents; purchase units must share the default unit’s category. That helps with configuration, but the actual version and modules need testing. Read the units documentation.

Why does “case” need a product-specific factor?

Do not apply one global case factor to every item: a case of screws might contain 24 pieces and a case of filters, 6. Record the supplier, pack, contents and effective period. If a supplier changes the pack, decide whether to create another presentation or a new version. Earlier transactions should preserve the factor under which they were accepted; changing the catalog should not reinterpret goods already dispatched.

Odoo distinguishes product-specific packaging and describes scanning configured packaging to add its contained units. Ask the demonstration to show the recognized product and contents before confirmation: the barcode image alone does not prove the conversion is correct. Packaging reference.

Worked example: change the pack, preserve the history

After U03, inspect U01: it must still show 72 pieces even though you now purchase CJ20. The return links to four pieces from U02 and their review status; the example assumes they are accepted back into available stock. If inspection is required, add physical stock to a blocked location without increasing availability. A return described as “one case” with no identified presentation should remain pending.

When should you weigh goods instead of converting?

For a variable-weight product, ten pieces do not necessarily equal a fixed weight. Retain piece count and measured net weight as separate data when your operation needs both. Document tare, scale precision and whether the reading was entered manually. Do not turn a commercial estimate into confirmed physical quantity. When receiving sacks, compare declared and accepted weight and retain the difference for review.

Also agree which fractions are valid. Issuing 0.5 pieces may be impossible for an indivisible item, whereas 0.125 kg may make sense. Define where rounding happens and how any remainder is handled; check a small transaction and its reversal. Several decimal places cannot compensate for an incorrect factor or the wrong unit. The person receiving goods should be able to see the measurement they are confirming.

Which tests distinguish a reliable conversion?

• Normal: receive and sell TOR-A in two units; the balance must match the table and each document must show its factor.
• Exception: try receiving CJ20 as CJ24, an unspecified case and a disallowed fraction; require a visible rejection or an identified review.
• Retry: lose U01’s confirmation and repeat it with the same reference; verify one movement. Changing its quantity under the same reference must produce a conflict rather than another silent receipt.
• Correction: amend a weight or pack with a reason, responsible person and original-event link; preserve the before and after.

Download the unit and pack acceptance worksheet. Replace the illustrative data with two of your products, including one with changing packs and another with decimals. Record the observed behavior and retain the delivery document and resulting history. Use the worksheet to compare options or prepare a scope; it does not replace the warehouse’s operational record.

Where does conversion end and wider inventory control begin?

Conversions alone do not decide reservations, valuation or return approval. Review the complete inventory control guide, then test barcode goods receipt. If the process needs adapting, the scope of an inventory management system should specify products, documents, permissions and evidence for these checks before selecting an implementation.