Inventory Cost Basis Calculator for Resellers

Allocate purchase price, inbound shipping, tax, repairs, and supplies across mixed resale inventory, then export a traceable per-item cost basis.

Allocate one lot cost across sellable inventory

Add the purchase price and shared acquisition costs, then allocate the landed total by units, weight, or a custom value share. The output is an operational COGS worksheet—not tax advice or a substitute for consistent books.

IRS sources checked 2026-08-17

Lot purchase price

Inbound shipping / freight

Purchase sales tax

Lot-level repairs

Lot-level supplies

Allocation method

Item allocation table

Custom shares are normalized, so 5/3/2 works the same as 50/30/20. Weight means total row weight.

Item / group	Qty	Weight	Custom share	Allocated	Per unit
Item name row 1	Quantity for Vintage jacket	Total weight for Vintage jacket	Custom share for Vintage jacket	$84.80	$84.80
Item name row 2	Quantity for Two pairs of shoes	Total weight for Two pairs of shoes	Custom share for Two pairs of shoes	$59.36	$29.68
Item name row 3	Quantity for Three basic tops	Total weight for Three basic tops	Custom share for Three basic tops	$25.44	$8.48

Landed lot cost

$169.60

Shared cost pool

Allocated total

$169.60

Reconciles to lot cost

Units

Across all rows

Allocation rows

Allocate by custom share

Landed lot cost = purchase price + inbound freight + purchase tax + lot repairs + lot supplies. Item cost = landed lot cost × item allocation weight ÷ total allocation weight.

Paste item rows from a spreadsheet

Use four columns: item, quantity, total weight, custom share. A header row is optional.

Save the audit trail

Export the inputs and allocation so each SKU can carry a traceable unit cost. Keep the original receipt, freight bill, tax, repair invoice, and allocation method with the file.

Which allocation method should a reseller use?

Equal per unit

Use when the units are similar enough that one unit should carry the same share of the lot. Do not use it when one high-value item clearly drove most of the purchase.

By weight

Use when acquisition cost follows weight or freight and the rows contain comparable merchandise. Weight is not automatically a fair proxy for resale value.

Custom share

Use an evidence-backed share when items differ materially. Save the reason—estimated replacement value, invoice detail, or another consistent rule—with the export.

IRS Publication 334 says merchandise purchase cost and freight-in are part of cost of goods sold and inventory practices must be consistent. Publication 538 describes specific identification when actual item costs can be matched. This calculator helps document a repeatable operational allocation; ask a qualified tax professional how your accounting method applies.

IRS Publication 334 IRS Publication 538 Inventory management guide