Toptal

This is the clearest walk-through of the exact trap you are in: your spreadsheet shows a healthy per-unit margin because unit economics only counts variable costs and quietly ignores fixed costs, so the business looks profitable long before it actually is. The author (a former VC-backed founder turned CFO) draws the contribution-margin-vs-fixed-cost lines and shows where they cross, which is the number you are really chasing. Treat it as a starting point for re-modeling with your fixed costs in, not as a verdict on your business.

Don't Scale an Unprofitable Business: Why Unit Economics (Still) Matter

From Toptal by Toby Clarence-Smith About a 15 minute read

• Positive unit economics and a cash-losing month are not a contradiction: per-unit margin covers variable costs only, and your rent, salaries, and tooling sit outside that math until you hit enough volume.
• The number to solve for is contribution margin times units minus fixed costs, so fix your model by adding the fixed-cost floor first, then see how many units it actually takes to cross zero.
• Bigger absolute margin per sale (not just a nice percentage) is what lets you grow into a fixed cost base, so a low-ticket product can bleed longer even with the same margin percent.