# Conversion Factor Session in Infor LN: Setup and Common Errors > Source: https://netray.co/erp-help/conversion-factor-session-in-infor-ln > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: ERP Help ## Short answer Infor LN converts between units using conversion factors, either general factors between units of the same physical dimension or item-specific factors that override them. When an item is bought in one unit and stocked in another, LN needs a factor for that pair. A missing factor is the usual cause of a conversion error on purchase orders, receipts or sales lines. ## Kind how-to ## System infor-ln ## Erp Infor LN ## Module Common Data / Item Base Data / Units ## Query conversion factor session in infor ln ## Alternate Queries - infor ln unit conversion factor - infor ln no conversion factor defined - infor ln purchase unit to inventory unit ## Applies To Infor LN 10.x. Session names for units and conversion factors sit in Common Data and Item Base Data; search the session list for 'conversion factors' in your version. ## Steps ### Fix a missing or wrong conversion factor **Items:** - Read the error and note the item and the two units LN is trying to convert, for example the purchase unit and the inventory unit. - Open the item's data and confirm its inventory unit, purchase unit, sales unit and any other units used. - Search the session list for the conversion factors session and check whether a general factor exists for the unit pair. - If units are of the same dimension, such as length, define the general factor. If not, such as converting a count to weight, define an item-specific factor. - Enter the factor in the correct direction. Confirm which unit the factor converts from and to, then test with a simple quantity. - Retry the transaction that failed, and check the quantity in the resulting order line and in inventory. - Review recently changed factors for open orders, since a change does not always revalue lines already created. ## Sections ### General versus item-specific factors **Body:** A general factor says, for instance, that a metre is a hundred centimetres, and applies to any item using those units. It only makes sense between units of the same physical dimension, because it relies on a fixed ratio. An item-specific factor describes a ratio that exists only for that item, such as a roll of material that weighs a known amount, or a pack of fifty pieces. These are the factors you must maintain item by item, and the source of most data-quality issues. ### Where factors are used **Body:** Purchasing converts the order unit to the inventory unit at receipt. Sales converts the sales unit to the inventory unit when reserving and shipping. Production may use another unit for bill of material quantities. Each of those boundaries needs a defined factor, or the transaction stops. Pricing can sit in yet another unit, so a mismatch may show as a wrong price per unit rather than an error. Check both quantity and price unit when totals look off. ### Preventing errors at scale **Body:** Create a standard unit set and conversion rules before item load. Use a data-load validation that, for every item, tests that each assigned unit pair has a factor, and flags rounding that loses precision, for example a factor that produces fractional inventory. Lock edits to factors for items with open orders unless a data owner approves, since a change affects receipts and valuation. **Code:** Item unit validation checklist For each item: inventory unit set? purchase unit -> inventory factor exists? sales unit -> inventory factor exists? BOM unit -> inventory factor exists? fractional quantity risk reviewed? ## Pitfalls - Entering a factor in the inverse direction and receiving a hundred times too many or too few. - Using a general factor for units from different dimensions. - Changing a factor while orders are open and assuming existing lines update. - Rounding that creates fractional quantities in a unit that must be whole. - Loading items with units in bulk without validating every unit pair. ## Ai Angle A data-quality sweep for missing or suspicious factors is a pattern-matching job. Netray's private assistant can scan item and unit data in read-only mode, list items with unit pairs lacking a factor or with implausible ratios, and draft the corrections for a data owner to approve and load. It runs on-prem, so item master data stays in your environment. ## Faq ### Which session maintains conversion factors in Infor LN? **Answer:** There are sessions in Common Data for general unit conversion factors and in Item Base Data for item-specific ones. Names and codes vary by version, so search the session list for conversion factors in your environment. ### What does 'no conversion factor defined' mean in LN? **Answer:** It means LN was asked to convert between two units and found no general or item-specific factor for that pair. Define the factor for the item or units involved and retry the transaction. ### When do I need an item-specific conversion factor? **Answer:** When the ratio between units is true only for that item, or when units belong to different dimensions, such as pieces to kilograms. General factors cover units of the same dimension. ### Will a changed factor update open orders? **Answer:** Do not assume so. Order lines already created may keep converted quantities. Review open orders after changing a factor and correct them deliberately, with a data owner's approval. ## Search terms infor ln conversion factor, infor ln unit conversion, infor ln no conversion factor, infor ln item units, infor ln purchase unit, infor ln conversion factors by item, baan unit conversion, ln inventory unit --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json