How do inventory UOM conversions work?

Owned by Tatum Hohl (Unlicensed)
Last updated: Aug 19, 2020 by Janice Dannenberg (Unlicensed)
5 min read

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Standard Rounding Rules

All Transactions display quantities in 5 decimal places. The item is then rounded to the quantity decimals setup on the item. For example, if the item is set to round to 4 decimals the quantity will have 1 trailing zero in the numeric textbox.

If an item is managed by units only…

  • Requires whole units→Round units to next whole number
  • Does not require whole units→Round units to Item’s Quantity Decimals

If an item is managed by weight only…

  • Requires whole units→Round weight to Item’s Quantity Decimals
  • Does not require whole units→Round weight to Item’s Quantity Decimals

If an item is managed by units and weight…

Is fixed weight…

  • Requires whole units…
    1. Round the units value to the next whole number
    2. Convert the rounded units value to the weight value
    3. Round the weight value to the Item’s quantity decimals
  • Does not require whole units…
    1. Round the units value to the Item’s quantity decimals
    2. Convert the rounded units value to the weight value
    3. Round the weight value to the Item’s quantity decimals

Is variable weight…

  • Requires whole units…
    1. Round the weight value to the Item’s quantity decimals
    2. Convert the rounded weight value to the units value
    3. Round the units value to the next whole number
  • Does not require whole units…
    1. Round the weight value to the Item’s quantity decimals
    2. Convert the rounded weight value to the units value
    3. Round the units value to the Item’s quantity decimals

Calculate on the Fly Rules

“Calculate on the fly” conversion rules pertain to when an item and/or its corresponding values, such as weight, units, or UOM, are changed on an open transaction. The rules below dictate what occurs when a specific change occurs on an open transaction, depending on the item’s setup.

When an item is changed on a transaction…

  • Resets all values and sets default values for Unit UOM and Weight UOM from the Item’s setup
  • If the item is managed by units only→disables the weight fields
  • If the item is managed by weight only→disables the units fields

When units are filled…

Item is managed by units only…

  • Requires whole units→Rounds units to the next whole number
  • Does not require whole units→Rounds units to the Item’s quantity decimals

Item is managed by units and weight…

  • Is fixed weight…
    • Requires whole units….
      1. Rounds the units value to the next whole number
      2. Converts the rounded units value to the weight value
      3. Rounds the weight value to the Item’s quantity decimals
    • Does not require whole units…
      1. Rounds the units values to the Item’s quantity decimals
      2. Converts the rounded units value to the weight value
      3. Rounds the weight value to the Item’s quantity decimals
  • Is variable weight…
    • Requires whole units…
      1. Rounds the units value to the next whole number
      2. Converts the rounded units value to the weight value
      3. Rounds the weight value to the Item’s Quantity Decimals

When the units UOM is changed…

Item is managed by units only…

  • Does nothing

Item is managed by units and weight…

  • Is fixed weight…
    • Requires whole units…
      1. Uses the units value to multiply by the conversion value to update the weight value.
        1. This assumes that since the unit value was already entered, the UOM change was not meant to affect the unit value.
      2. Rounds the weight value to the Item’s quantity decimals
    • Does not require whole units…
      1. Uses the units value to multiply by the conversion value to update the weight value.
        1. This assumes that since the unit value was already entered, the UOM change was not meant to affect the unit value.
      2. Rounds the weight value to the Item’s quantity decimals
  • Is variable weight…
    • Requires whole units…
      1. Does nothing

When the weight is filled…

Item is managed by weight only…

  • Requires whole units→Rounds the weight value to the Item’s quantity decimals
  • Does not require whole units→Rounds the weight value to the Item’s quantity decimals

Item is managed by units and weight…

  • Is fixed weight…
    • Requires whole units…
      1. Rounds the weight value to the Item’s quantity decimals
      2. Uses the rounded weight value to multiply by the conversion value to get the new units value
      3. Round the new units value to the next whole number
      4. Uses the rounded units value to multiply by the conversion value to update the weight value
      5. Rounds the weight value to the Item’s quantity decimals
    • Does not require whole units…
      1. Rounds the weight value to the Item’s quantity decimals
      2. Uses the rounded weight value to multiply by the conversion value to get the new units value
      3. Round the new units value to the Item’s quantity decimals
      4. Uses the rounded units value to multiply by the conversion value to update the weight value
      5. Rounds the weight value to the Item’s quantity decimals
  • Is variable weight…
    • Requires whole units…
      1. Rounds the weight value to the Item’s quantity decimals
      2. Used the rounded weight value to multiple by the conversion value to get the new units value
      3. Rounds the units value to the next whole number

When the weight UOM is changed…

Item is managed by weight only…

  • Does nothing

Item is managed by units and weight…

  • Is fixed weight…
    • Requires whole units…
      1. Uses the units value to multiply by the conversion value to update the weight value
      2. Rounds the weight value to the Item’s quantity decimals
    • Does not require whole units
      1. Uses the units value to multiply by the conversion value to update the weight value
      2. Rounds the weight value to the Item’s quantity decimals
  • Is variable weight…
    • Requires whole units…
      1. Does nothing
  • Does not require whole units…
      1. Does nothing

Note: All inventory is reported in the Item’s reporting UOM, including Lots. 


Conversion Rules for Non Default UOMs

Any Items that are saved on a transaction that have the units and/or weight UOMs set to the Default Inventory Unit UOM or Default Inventory Weight UOM, there is no need for any conversions and we will save the “Effect On Inventory” as the amount filled in by the user. The interface will uphold the Require Whole Units, Fixed Weight vs Variable Weight, Unit Decimals, Weight Decimals, etc.

If any items that are saved in a non default unit of measure (Inventory Unit UOM or Inventory Weight UOM), then the following calculations will happen:

Item is managed by units only...

  • We convert the Unit quantity from the transaction to the default unit UOM quantity rounded to the unit decimals precision
  • We then save the effect on inventory unit of measure and the conversion rate used at that time
  • At this time, there is no UI for these fields but will be soon

Item is managed by weight only...

  • We convert the weight quantity from the transaction to the default weight UOM quantity rounded to the weight decimals precision
  • We then save the effect on inventory unit of measure and the conversion rate used at that time
  • At this time, there is no UI for these fields but will be soon

Item is managed by units and weight...

  • Is variable weight...
    • We convert the unit quantity from the transaction the the default unit UOM quantity rounded to the unit decimals precision
    • We convert the weight quantity from the transaction to the default weight UOM quantity rounded to the weight decimals precision
    • We then save the effect on inventory unit of measure for both units and weight and the associated conversion rates used at that time
  • Is fixed weight...
    • We convert the unit quantity from the transaction to the default unit UOM quantity rounded to the unit decimals precision
    • We convert the default unit quantity to the default weight quantity rounded to the weight decimals precision
    • We then save the effect on inventory unit of measure for both units and weight and the associated conversion rates used at that time


Allocating

  • For variable weight items or items that don’t require whole units, you can wind up having conversions that will never work (remainder of .0001 for example). If you are allocating all of a specific lot, no matter the unit of measure it is in, we will automatically allocate the remainder of the lot in the default unit of measure. This is to ensure you don’t wind up having lots that have remainders that have to do with rounding issues. Of course this won’t solve ALL problems but will certainly solve most of them.