Luminous provides two dedicated import tools under Tools → Imports → Costs & Finance for bulk-managing the cost layers attached to your SKUs. They serve different purposes:
| Tool | What it does |
|---|---|
| FIFO Cost Layer Multi-Value | Replaces all existing cost layers for a SKU/warehouse with a fresh set of layers you define |
| Unit Cost Override | Updates the unit cost on existing active cost layers in place, without changing quantities or replacing layers |
Before you start: Both imports are destructive to cost data. Download and review the template first, and run a small test batch before processing your full catalog.
Tool 1 — FIFO Cost Layer Multi-Value Import
Use this when you need to seed or reset the cost-layer history for one or more SKUs — for example, after a beginning-balance migration or a significant cost correction.
How it works
- All existing cost layers for each SKU + warehouse combination in your file are deleted before new ones are created.
- New layers are inserted in the order they appear in your file (oldest purchase date = first FIFO layer).
- Total on-hand stock is always preserved — the import reconciles layer quantities to match your current stock; it does not change actual inventory quantities.
Step-by-step
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Go to Tools → Imports, then open the Costs & Finance section.
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Click FIFO Cost Layer Multi-Value.
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Choose your import mode (see below), then download the Excel template.
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Fill in the template. Each row is one cost layer:
Column Required? Notes SKU Yes Accepts your internal SKU, any alternate SKU, or UPC WAREHOUSE Yes Exact warehouse name as it appears in Luminous PURCHASE_DATE Yes Format: YYYY-MM-DD. Determines FIFO order; falls back to today if blank or invalid UNIT_COST Yes Must be greater than zero QUANTITY Mode B only Leave blank in Mode A; required in Mode B -
Upload the completed file and review any validation errors. No changes are saved if the upload fails.
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After a successful import, open Inventory, click into the SKU, and check the Cost or Cost Layers tab to confirm the new layers.
Import modes
Mode A — Use Current Stock Levels (QUANTITY column left blank)
- The system reads the SKU's current on-hand quantity in that warehouse.
- It divides that quantity evenly across all the rows you provided.
- Use this when you want to set costs without worrying about how many units belong to each layer.
- SKUs with zero on-hand are skipped (no layers are created).
Mode B — Import Quantities (QUANTITY required on every row)
- You specify exactly how many units each layer contains.
- If your imported totals do not perfectly match current stock, the system automatically adjusts the oldest layer's quantity to reconcile the difference.
- If the adjustment would make the oldest layer go negative, the import fails with an error — you must correct the quantities before retrying.
Validation rules
- SKU must exist and be active.
- Warehouse must be an active warehouse in Luminous.
- Unit cost must be greater than zero.
- In Mode B, quantity must be greater than zero per row.
- The system cannot distribute stock when on-hand is negative; this will produce an error.
Tool 2 — Unit Cost Override Import
Use this when your cost layers already exist (from receiving, count adjustments, etc.) but the unit cost recorded on them is wrong and you want to correct it in bulk.
Note: This tool may not be visible in your account — it is enabled on a per-tenant basis. Contact support if you do not see it.
How it works
- The import finds all active cost layers for the given SKU + warehouse (optionally filtered to a specific creation date) and updates their unit cost and total cost in place.
- Layer quantities and FIFO order are not changed.
- Every override is recorded in the cost-layer audit trail with the original and new cost per unit.
- Rows where the warehouse is not found, or where no active cost layers exist for that SKU + warehouse, are silently skipped (not treated as errors).
Step-by-step
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Go to Tools → Imports, then open the Costs & Finance section.
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Click Unit Cost Override.
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Download the Excel template.
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Fill in the template. Each row targets one SKU + warehouse combination:
Column Required? Notes MASTER_SKU Yes The SKU whose layers you are correcting WAREHOUSE Yes Exact warehouse name DATE_CREATED_FIELD No If provided, only layers created on or before this date are updated. Leave blank to update all active layers for that SKU + warehouse UNIT_COST Yes The new cost per unit to apply -
Each MASTER_SKU + WAREHOUSE combination may appear only once per file — duplicates are rejected.
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Upload the file. The import processes each row inside its own transaction; a failure on one row does not affect others.
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After the import, open the SKU's Cost Layers tab to verify the updated costs.
Choosing the right tool
| Situation | Recommended tool |
|---|---|
| Starting fresh — you want to define brand-new FIFO layers from scratch | FIFO Cost Layer Multi-Value |
| Correcting a cost that was entered incorrectly on a receipt | Unit Cost Override |
| You received stock at the wrong cost and want to fully restructure the layer history | FIFO Cost Layer Multi-Value |
| You just want to reprice existing layers without touching quantities | Unit Cost Override |
Common errors and fixes
| Error message | Cause | Fix |
|---|---|---|
| "The selected SKU does not exist" | SKU not found in Luminous | Double-check the SKU, alternate SKU, or UPC spelling |
| "The selected warehouse does not exist" | Warehouse name mismatch | Copy the warehouse name exactly from Luminous settings |
| "Unit cost must be greater than zero" | Zero or negative cost entered | Ensure UNIT_COST is a positive number |
| "Quantity is required when import mode is import_quantities" | QUANTITY column left blank in Mode B | Add quantities to every row, or switch to Mode A |
| "Cannot reconcile imported quantities with current stock" | The adjustment needed would make the oldest layer's quantity go negative | Reduce the quantities in your file or align them more closely to the actual on-hand count |
| "A record with the same warehouse and master_sku already exists" | Duplicate SKU + warehouse row in Unit Cost Override file | Each SKU + warehouse pair must appear only once per upload |