| LED tubing, acrylic backing, power supply, wiring, and direct production labor |
Variable |
Model per sign; first-year direct inputs range from $25 to $75 per unit by product. |
Using one blended input amount and missing product mix. |
| Marketing & advertising |
Variable |
Apply 4.0% of revenue in the first year, then use the year-by-year revenue percentages. |
Entering it as a flat monthly budget. |
| Payment processing fees |
Variable |
Apply 2.0% of revenue in the first year, then use the year-by-year revenue percentages. |
Treating card fees as fixed overhead. |
| Workshop & office rent |
Fixed |
Include $3,500 per month in fixed overhead from Month 1. |
Allocating rent per sign and overstating margin at higher volume. |
| Website & e-commerce platform |
Fixed |
Include $400 per month as recurring platform overhead. |
Mixing one-time setup spend with monthly operating expense. |
| Salaried operating team |
Semi-fixed |
Add payroll in FTE steps by year for founder, design, production, marketing, and admin roles. |
Modeling salaries as a direct percent of sales. |
| Workshop usage and production overhead |
Semi-variable |
Split the $800 monthly utilities base from revenue-tied shop utilities, maintenance, quality control, supplies, and production software fees. |
Treating the $35,000 laser cutter purchase as monthly operating expense. |