Any solution for BC's item number 20 character limit?

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Posted on by LL-11041800-0

We are migrating our data from GP to BC. However, BC has a 20 character limit on item numbers. Changing the item number will heavily impact our company. We are wondering if there are any workarounds?
Only solution I can think of right now:
i. Create a custom dictionary table for all our items, with “Item Number” = 1,2,3, … to 46074, and “Part Number”, which is our true item number.
ii. Modify our SQL tables, replacing our current item number with 1,2,3,…
iii. After migration, whenever we want to display item number, we use AL to lookup and display “Part Number”.

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Dynamics 365 Business Central

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Saif Ali Sabri 2,360 Moderator on at

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You're correct—Business Central enforces a 20-character limit on the No. field for items, and altering this limit directly is not supported. Here are two practical solutions:
Option 1: Custom Mapping Table (Your Suggested Approach)

Create a custom table with fields: Item No. (short key), Part Number (full original).

Use a generated short code (1, 2, 3...) as the actual Item No. in BC.

Override display and lookup logic in AL to show/use the Part Number wherever needed (pages, reports, APIs).

Pros: Retains original part numbers logically.

Cons: Additional dev overhead for UI, reports, and integrations.

Option 2: Use External ID with Item Cross Reference

Use the standard Item Cross Reference feature to store the original GP Part Number as a cross-reference.

Set up a consistent Cross-Reference Type (e.g., "GP").

Use customization or reporting logic to pull/display Part Number where needed.

Pros: No heavy dev; utilizes built-in BC features.

Cons: Still requires some customization for visibility in UI/reporting.

⚠️ Avoid trying to alter table schema directly; it's unsupported and will break updates and AL extensions.
Let me know if you'd like a sample AL code snippet or guidance on setting up either method.

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Jainam M. Kothari 16,158 Super User 2026 Season 1 on at

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Hello,

To address the 20-character limit on item numbers in Business Central during your migration from GP, you can create a custom dictionary table mapping your original item numbers to shorter ones, modify your SQL tables accordingly, and use AL to display the full item numbers post-migration.

Alternatively, consider using custom fields, item cross-references, or item variants to manage the original item numbers without significant impact on your operations.

https://thecentraltech.com/community/microsoft-dynamics-365-business-central-technical/enter-item-numbers-of-more-than-20-characters/

https://www.reddit.com/r/DynamicsNAV/comments/fo7l26/business_central_increase_item_no_field_length_to/?rdt=48690

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Teddy Herryanto (Th... 14,306 Super User 2026 Season 1 on at

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BC does have a limitation of 20 characters for the item code.

You can put the GP Code as an Item Reference so the user can still use their old GP Code.

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Khushbu Rajvi. 22,350 Super User 2026 Season 1 on at

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Business Central's standard Item.No. field is limited to 20 characters and cannot be extended directly due to base table limitations. Microsoft doesn't support increasing that length, even in On-Prem environments. The workaround using a custom mapping table with a short internal number and a full external part number is a well-known and commonly implemented solution. It’s used in many GP to BC migrations where longer item numbers are involved.

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