A lower unit price does not always mean a lower total cost.
Include extra costs
Total = unit price × quantity + extra costs. Add known shipping, installation or other fixed charges in the extra-cost field. Do not include an amount there if it is already part of the unit price.
A worked comparison
Option A: three items at 20 plus 10 shipping total 70. Option B: three items at 22 with no extra fee total 66. B costs four less overall despite having the higher unit price.
Compare like with like
Use the same currency and the same unit, such as kilograms rather than mixing kilograms with grams. The calculator does not convert currencies, estimate taxes or fetch prices. If quantities differ, check the cost-per-unit column as well as the total.
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