Margin & Markup
COGS → price, margin %, markup % — or back-solve any missing number. Add platform fees, shipping, and sales tax to see **true unit economics** and totals by quantity.
Inputs
Margin = (Price − Cost) / Price
Markup = (Price − Cost) / Cost
Fees, shipping & tax (optional)
Tax is passed through; it does not affect margin unless you absorb it.