The calculation, step by step
- Normalize compatible units, then round required packs up to a whole pack.
- Multiply packs by pack price and subtract the stated goods discount.
- Apply the stated duty percentage to discounted goods.
- Add shipping, then apply the stated tax percentage to that subtotal.
- Add other fees outside the tax base. Divide total by delivered quantity for cost per delivered unit.
A worked example
Need 25 pieces, sold in packs of 12 at 24 USD? Buy 3 packs: 36 pieces, 11 extra. With 10 USD freight, no discount, no duty, 5% tax and zero other fees, the scenario total is (72 + 10) × 1.05 = 86.10 USD. That is 2.39167 USD per delivered piece.
Choose the right assumptions
All charges use the same declared currency. Tax and duty bases vary by jurisdiction and transaction. This tool uses the explicit model shown above; it does not provide tariff rates, tax advice, incoterm rules, recoverable-VAT treatment or supplier minimum-order enforcement. Confirm the model and every input before placing an order. Blank costs prevent a result.
Unit definitions use the NIST-based practical registry, reviewed 4 October 2026. The cost formula is Tabel's transparent scenario model. Use the dated currency reference for context, then use your actual transaction rate for purchasing.
Keep the whole comparison in view
Have several supplier spreadsheets? Open the comparison desk to map columns, review identity and preserve source evidence.