Identify the denominator
A percentage charge needs a stated base, usually a quoted metal value; a per-gram charge needs a stated weight basis; a fixed charge applies to the described item or job. Ask whether each method is an alternative or whether the seller adds more than one. The comparison calculator treats them as alternatives.
Use one consistent metal value
Enter the same purity-specific rate and net metal weight for all alternatives. Percentage charge = rate × net grams × percentage / 100. Per-gram charge = net grams × quoted charge per gram. Compare those results with the fixed quotation before adding any tax assumptions.
Check what a discount changes
A discount on making charges is not necessarily a discount on the whole bill. Ask how wastage, stones and other services are charged, and which amounts are discounted. Save the full estimate and compare the written total. Making charges may not be recovered on resale; confirm the buyer's actual terms.