Type any two of cost, price, or margin — the third fills in. Pin a value to lock it.
Unit cost
$
What you pay for it
Sale price
$
What you charge
Gross margin
%
Profit as % of price
Gross profit per unit
—
Price minus cost
Markup (on cost)
—
How much you mark cost up
Markup ≠ margin. A 50% markup is only a 33% margin. A 100% markup is a 50% margin. They're calculated from different bases — markup off cost, margin off price — which is why estimates always look better in markup and bank statements always look worse in margin.
Pricing a whole catalog?
If you're solving this for one product, a calculator's fine. If you're pricing parts, services, or SKUs in bulk — and need margin to hold up across discounts, taxes, and tradesperson commissions — that's what GearShift (automotive) and DealDesk (B2B quotes) actually do. SiteLine builds it into every estimate.