Two percentages with different denominators
Markup describes an increase over cost. Profit margin describes the share of sales left after the costs included in your model. Confusing them can produce a selling price that misses your target even before payment fees.
Work at the order level
Enter production cost per part and the quantity in one order. Add shipping, one-off project work and any fixed transaction fee. Project work can cover design, file repair or customer communication that happens once for this order rather than once for every printed part.
Set project work to zero when it does not apply. If a reusable design cost should be recovered across several expected orders, allocate only the defensible share for this quote instead of charging the full amount repeatedly. The percentage fee applies to the complete quoted order amount.
Use a minimum only as a selling-price floor
Tiny orders can still consume setup and communication time. If you have a genuine minimum order policy, enter the minimum total for the whole order. The calculator uses the greater of that floor and the cost-and-margin result; it does not add the minimum on top.
A minimum is not a hidden cost or proof that the market accepts the price. Set it to zero when you have no policy, explain the amount to the customer where appropriate, and keep real project work in the separate project-work input.
Understand the rounding
The order result is divided by quantity, and the per-part price rounds upward to cents for USD/EUR or whole won for KRW. The displayed order total is that rounded unit price multiplied by quantity, so the actual modeled margin may be slightly above the target.
Changing the currency label does not convert any amounts. When switching currency, replace all prices, shipping and fee values with numbers in that currency. The calculator does not obtain exchange rates.
Know what the result leaves out
The model is before tax and excludes discounts, refunds, advertising acquisition cost and overhead you have not entered. Use project work for real one-off labor, not as an unexplained buffer. If recurring overhead matters, include a defensible allocation and check it against your own records.
A mathematically valid price is not proof that customers will buy. Fee plus target margin must be less than 100%; otherwise the denominator cannot produce a usable positive price. Zero entered costs can produce a zero quote, which is not a business recommendation.