SUPPLIER FILES · WORKED EXAMPLE
Compare supplier costs by SKU before you change a price.
Match each product by its unique SKU, map the cost columns in both files and review the changes. Row position is unreliable: a supplier can reorder the same products without changing their costs.
This fictional candle example uses the sample files in CatalogDiff’s free preview. Costs are GBP per unit, excluding VAT. It illustrates a review process and makes no claim about a real supplier.
Start by checking what each column means
The current file calls its key SKU and its cost Cost. The new file calls them Part Number and Unit Net. Map those pairs before comparing values. Product names help a human check the match, but should not replace a stable key.
SKU,Name,Cost CANDLE-01,Amber candle,7.50 CANDLE-02,Cedar candle,8.00 CANDLE-03,Citrus candle,6.00 CANDLE-04,Fig candle,5.00
Part Number,Unit Net,Description CANDLE-02,8.0000,Cedar candle CANDLE-01,8.50,Amber candle CANDLE-03,3.80,Citrus candle CANDLE-05,7.00,Rose candle
Separate price changes from catalogue changes
| SKU | Current cost | New cost | Review |
|---|---|---|---|
| CANDLE-01 | £7.50 | £8.50 | Increase £1.00, about 13.3% |
| CANDLE-02 | £8.00 | £8.0000 | Same numeric cost |
| CANDLE-03 | £6.00 | £3.80 | Decrease £2.20, about 36.7% |
| CANDLE-04 | £5.00 | Missing | Check the supplier’s scope |
| CANDLE-05 | New | £7.00 | Confirm the product match |
A missing row does not prove a product is discontinued. The file might contain only one range or only changed products. Confirm its scope before removing a listing. A large decrease deserves attention too: check that a pack of six has not become a single item.
Resolve bad keys before approving anything
Every row needs one non-empty, unique SKU. If two rows share a key, a comparison cannot safely decide which product you mean. Keep leading zeros: SKU 0007 may be different from 7. Inspect the actual file after exporting it from a spreadsheet.
Check currency, tax treatment, pack size and quantity breaks separately. Comparing a VAT-inclusive retail price with an ex-VAT unit cost produces a number with no useful business meaning. This preview supports GBP unit costs excluding VAT only.
Approve the evidence you have reviewed
In the prepared offline edition of CatalogDiff, choose the SKU and cost columns for each file, compare them, then approve individual changed costs after checking the product. Editing the inputs marks the comparison as stale. Running the comparison again clears the previous approvals.
The online preview handles up to 50 rows per file. The prepared offline edition adds saved reviews, reusable mappings and exports for up to 5,000 rows per file. Its planned price is £39; paid sales are currently closed.
Exports are review records. They are not ready-made Shopify or other platform import files. Check your destination’s required schema, keep a backup and verify the resulting changes before treating an import as complete.
A higher cost does not choose your selling price
For Amber candle, the increase is (8.50 − 7.50) ÷ 7.50 × 100 = 13.33…%. That describes the supplier’s cost change. Your selling-price decision also depends on fees, packaging, labour, overheads and margin. BatchPrice can help explore a separate pricing calculation.
Open CatalogDiff and load the worked example →
Written 7 September 2026 by Aftercart Studio. Based on the included original sample files and current tool behaviour.