The quick answer
A custom list is not a matrix option on items until a custom item field uses it. Go to Customization > Lists, Records, & Fields > Item Fields and click New. Enter a Label and an ID, tick Matrix Option and choose your list in List/Record. Ticking the box sets Type to Multiple Select, keeps Store Value checked and sets the Display subtab to Matrix. On Applies To, tick the item types that will use the option, such as Inventory Item, and save. Create Matrix Items for that item type then shows a box for the list on Accounting > Matrix Items.
The screenshots show sample data. Person and company names are fictional. Use your own lists and field names when following the steps.
Before you start
Example Supply Co. has a Strap Length custom list with three values, 2 m, 3 m and 5 m, flagged as a matrix option list. The list is there, but a new matrix item does not offer it. NetSuite needs one more record for each dimension: a custom item field marked Matrix Option that points at the list. The list holds the values and the field puts them on the item. One list and one field make one dimension, so a second list, such as a webbing material, needs its own field.
The account needs the Matrix Items feature, under Setup > Company > Enable Features > Items & Inventory. The label can differ by release. Your role needs permission to create custom item fields. Each value of the list needs an abbreviation of up to 15 characters. Whether an abbreviation appears in the generated item names depends on the Matrix Item Name Template you use.
This setup is only configuration for the next matrix you create. It does not change items that already exist, create combinations or fill any values. Try it in a sandbox first if you have one.
01. Check the starting point
Go to Lists > Accounting > Items > New. On the Inventory Item row, click Create Matrix Items. The Inventory Item form opens with a Matrix tag under the title. Open the Accounting subtab and scroll to Matrix Items. There is one selection box for each existing matrix option. Here they are Color and Width, and there is no Strap Length box. Leave the form without saving.
02. Open a new item field
Go to Customization > Lists, Records, & Fields > Item Fields. The Custom Item Fields page lists the existing fields. The Color and Width fields are Multiple Select, use the list of the same name and have Matrix as their tab. Click New.
03. Name the field and make it a matrix option
In Label, enter the name users will see on the item, here Strap Length. The label must not repeat another custom item field. In ID, enter _strap_length. NetSuite adds the custitem prefix when you save, so the field is stored as custitem_strap_length. Choose the ID on purpose if scripts, searches or imports will refer to it.
Tick Matrix Option. Type changes to Multiple Select by itself and Store Value stays checked but can no longer be cleared in the release tested. The type is Multiple Select because a matrix parent holds every value it is sold in while each child holds exactly one. Then set List/Record to the list that holds the values, here Strap Length.
04. Choose the item types and check the display
On the Applies To subtab, tick the item types that will carry the option. Here only Inventory Item is ticked. Applies To does not turn a parent into another item type. A parent is still created from the Create Matrix Items link on the row for its own type. In the account tested, that link is offered for assembly, inventory, non-inventory, other charge and service items, and not for item groups or kits. If you also tick Non-inventory Item, Service, Other Charge or Assembly/Bill of Materials, create each matrix parent from the link for that type.
Open the Display subtab. Subtab is already Matrix and Display Type is Normal, so the field sits with the other matrix options. You do not need to change anything here.
05. Save the field
Click Save. NetSuite returns to the Custom Item Fields list and confirms Custom Item Field successfully Saved. The new row shows Strap Length with the ID custitem_strap_length, the type Multiple Select, the list Strap Length, the tab Matrix and Y under Inventory Part. The column is named Inventory Part, while the Applies To box on the form is named Inventory Item. They are the same item type, so check the ID, type, list and tab as well as the Y.
06. Confirm the parent offers the option
Go to Lists > Accounting > Items > New and click Create Matrix Items on the Inventory Item row again. On Accounting > Matrix Items, a Strap Length box now sits beside Color and Width. It lists 2 m, 3 m and 5 m, the values of the list. The Apply to Forms button was not used. In the account tested, the box showed on the standard form without it. A custom form, a role or a form customization can still hide or move the box, so check the form your users work with.
Check the result
- The Custom Item Fields list has a Strap Length row with the ID custitem_strap_length.
- The row shows Multiple Select, the list Strap Length, the tab Matrix and Y under Inventory Part.
- Create Matrix Items on the Inventory Item row shows a Strap Length box.
- The box lists 2 m, 3 m and 5 m.
On a parent, a selection box holds several values at once. Hold Ctrl, or Cmd on a Mac, while clicking to select more than one. A value you add to the list later becomes selectable, but nothing is created until the matrix items are created. Adding the field does not change items that already exist.
Common questions
Why doesn't my custom list show up as an option on a matrix item?
A list on its own is not an option on items. A custom item field marked Matrix Option, with the list chosen in List/Record, has to use it, and the field has to apply to the item type you are creating. Each list needs its own field. If the box is still missing, check that the Matrix Items feature is on, the list is active, marked Matrix Option List and has values with abbreviations, the field is active and applies to the item type, and your role and the item form show it. A form, a role or a form customization can hide or move the box. Reload the page after saving the field.
How do I create a matrix option custom item field?
Go to Customization > Lists, Records, & Fields > Item Fields and click New. Enter a Label and an ID, tick Matrix Option, choose the list in List/Record, tick the item types on Applies To and save.
What does the Matrix Option check box do on a custom item field?
It marks the field as a matrix option. In the release tested, ticking it set Type to Multiple Select, kept Store Value checked but locked, and set the Display subtab to Matrix. It also leaves Print on Price List unavailable.
Do I need a separate item field for each matrix option list?
Yes. Each dimension is a pair of one list and one field. A Strap Length list and a Strap Webbing list each need their own custom item field.
Why does a matrix option field have the type Multiple Select?
A matrix parent holds every value it is sold in, such as all three strap lengths, and each child item holds exactly one. Multiple Select lets the parent store several values, so NetSuite sets it for you when you tick Matrix Option.
Does selecting values in the Strap Length box create the items?
No. The box only chooses which values this parent is sold in. Items are created when you create the matrix from the parent. NetSuite limits how many children one parent can have, with 2,000 combinations as the figure quoted, and the count is the product of the values selected in every box. Check the current help for your account before planning a large matrix.
Do abbreviations appear automatically in the item names?
Not by themselves. The generated names follow the Matrix Item Name Template on the parent, and the template has to include every matrix option. Whether you build names from the values or from the abbreviations is a choice you make there. Generated names must be unique.
Does this make the option selectable on a web store?
Not on its own. The field sets up the internal matrix. Showing a choice to shoppers is a separate commerce setup, such as a transaction item option, so check it with your web store team.
Where do matrix option fields show up on an inventory item?
On a matrix parent they show on Accounting > Matrix Items as one selection box per option. That is where the Display subtab of the field, Matrix, puts them.
Does a new matrix option field apply to existing matrix items?
No. It is configuration for the next matrix you create. It does not add the dimension to children that already exist, create combinations or fill values. Settle the list, the item types and the Matrix Option setting before items use the field, because changing them afterward may be restricted.
Do I have to use Apply to Forms for a matrix option field?
Not in the account tested. The Strap Length box showed on a new Inventory Item matrix parent without it. If your users work on a custom form, the box may not show until the field is on that form, so check with a real user's role and form.
What does ID _strap_length become?
NetSuite adds the custitem prefix when you save, so _strap_length is stored as custitem_strap_length. Choose it deliberately if scripts, saved searches or imports will refer to the field.