Use one currency consistently. Figures are estimates, not forecasts. Change every sample number to your own. Taxes, refunds, insurance, unsold-stock write-offs and business-wide overhead are excluded unless you add them under other costs. Do not add the same cost twice.
Expected sales = buyers × average spend. Product cost = sales × product-cost rate. Card fees = sales × card share × card-fee rate. Fixed event cost = booth + travel + other + (total hours × chosen hourly value). Contribution = sales − product cost − card fees − fixed event cost. Break-even sales = fixed event cost ÷ (1 − product-cost rate − card share × card-fee rate). Buyers needed = break-even sales ÷ average spend, rounded up.
If a dollar of sales cannot cover its variable costs, break-even is impossible; if hours are zero, hourly return is undefined. Compare not just the larger figure but the uncertainty in buyer count and your own time.
Category context: Farmstand’s free market profit calculator covers single-day cost estimation; this tool focuses on a side-by-side invitation decision. A competing paid booth planner advertises stock and product-mix features this tool does not offer. Neither listing establishes demand for this Tigi Labs kit.