How This Sales Calculator Works
This tool helps you translate messy, real‑world assumptions into clean unit economics you can defend. Start with units, list price, and any discounts you expect to offer. Choose tax mode—exclusive or inclusive—so the engine treats VAT or GST correctly. Add returns and refunds to capture revenue leakage, then include shipping charged to customers and the actual shipping, pick/pack, and packaging costs you incur per order. Fees cover your payment service provider, marketplace commissions, and any affiliate costs. Marketing spend, especially customer acquisition cost per order, is treated as a variable expense by default for transparent contribution margin. Finally, monthly overhead is allocated back using your estimated orders per month to reveal an EBITDA‑like operating result.
Key Formulas
Price after discounts = list_price × (1 − discount%) − discount$. If tax is inclusive, we back tax out; otherwise we add tax when computing amounts collected. Net revenue excludes tax and refunds: units × price_ex_tax + orders × shipping_charged − refund_amount. Gross profit = net_revenue − COGS. Contribution margin subtracts all variable costs (shipping cost, payment and marketplace fees, affiliate, return costs, and CAC): net_revenue − variable_costs. EBITDA (approximate) = contribution − allocated_overhead. Break‑even units estimate fixed cost coverage using unit contribution including overhead allocation.
Revenue ladder (per period)
| Step | Definition |
|---|
| List Revenue | units × list_price |
| Promo & Discounts | Percent and fixed reductions from list |
| Price ex Tax | Price net of VAT/GST when inclusive |
| Shipping Charged | Customer shipping fees collected |
| Refunds | units × return_rate × refund% × price_ex_tax |
| Net Revenue | After deducting tax pass‑through and refunds |
Variable Costs and Contribution
Variable costs scale with sales volume or orders. Shipping cost per order combines carrier charges, pick/pack, and packaging. PSP fees typically include a percentage of the gross amount collected plus a fixed fee per order. Marketplaces take a percentage of item revenue and sometimes per‑order charges. Count affiliate commissions on the same base as your program stipulates. Customer support and warranty can be included via a small “return cost per unit.” Add CAC per order to reflect marketing. Subtracting these from net revenue yields contribution dollars and percentage, the clearest indicator of unit profitability before overhead.
| Component | Per‑Unit/Order | Included In | Notes |
|---|
| COGS | Per unit | Variable costs | Materials, labor, inbound freight, duty |
| Shipping Cost | Per order | Variable costs | Carrier + pick/pack + packaging |
| PSP Fees | % + fixed | Variable costs | Percent on collected amount plus fixed |
| Marketplace Fees | % + fixed | Variable costs | Channel commission and closing fees |
| Affiliate | % of revenue | Variable costs | Tracking per program rules |
| Return Costs | Per unit | Variable costs | Reverse logistics, refurbish, disposal |
| CAC | Per order | Variable costs | Blended marketing acquisition spend |
Break‑Even, Elasticity, and Pricing
The break‑even view intersects revenue and total cost lines to show the output required to cover fixed overhead. The profit‑versus‑price chart applies a simple elasticity assumption to illustrate how price changes may affect demand; use it to locate profitable price neighborhoods rather than a single point. For promotions, compare scenarios—baseline, percent‑off, free shipping threshold, or marketplace—to visualize gross margin, contribution, and EBITDA side by side. Export CSV for audit trails and a PDF report that snapshots KPIs and charts for stakeholders.