What is Gross Margin?

Gross margin is the share of each sales dollar you keep after paying the direct costs of producing or delivering what you sold. If you sell something for $100 and it costs $30 to make and ship, your gross profit is $70 and your gross margin is 70%.

Those direct costs are called cost of goods sold (COGS) — the hosting, materials, payment fees, and support directly tied to serving a customer. Gross margin tells you how much money is left over to cover everything else and eventually turn a profit.

Why margin shapes everything

Gross margin sets the ceiling on how much you can spend to acquire customers and still survive. Software businesses often run 70–90% margins, which is why they can afford expensive growth. Physical-product and marketplace businesses run far thinner, so they have to be much more careful.

• High margin (software): lots of room to invest in growth and absorb mistakes.
• Low margin (retail, hardware): every cost must be controlled tightly.
• Gross margin feeds directly into LTV — higher margin means each customer is worth more.

Why gross margin matters for validation

A great-looking revenue number can hide a terrible business if margins are thin. Knowing your realistic gross margin early tells you whether an idea can ever generate enough profit per sale to cover acquisition and overhead. Two companies with identical revenue can have completely different futures depending on margin.