Calculator Inputs
Example Data Table
| Input | Example Value | Purpose |
|---|---|---|
| Fixed Costs | $5,000.00 | Monthly platform, payroll, rent, and tools. |
| Selling Price Per Unit | $55.00 | Average selling price for one item. |
| Product Cost Per Unit | $18.00 | Direct product sourcing cost. |
| Fulfillment + Packaging | $6.00 | Handling, packing, and dispatch costs. |
| Ad Cost Per Unit | $6.00 | Paid acquisition cost per order. |
| Total Variable Cost Per Unit | $35.10 | Estimated unit cost after fees and returns. |
| Break Even Units | 251 | Rounded units needed to cover fixed costs. |
Formula Used
Payment fee amount = (Selling Price × Payment Fee %) + Fixed Payment Fee
Marketplace fee amount = Selling Price × Marketplace Fee %
Expected return cost = Return Rate % × Loss Per Returned Unit
Variable Cost Per Unit = Product Cost + Fulfillment + Packaging + Ads + Payment Fee Amount + Marketplace Fee Amount + Expected Return Cost
Contribution Margin = Selling Price − Variable Cost Per Unit
Break Even Units = Fixed Costs ÷ Contribution Margin
Break Even Revenue = Break Even Units × Selling Price
Target Profit Units = (Fixed Costs + Target Profit) ÷ Contribution Margin
The calculator rounds required units upward because you cannot sell a fraction of a unit in most ecommerce operations.
How to Use This Calculator
Enter your fixed business costs for the chosen period, such as monthly software, salaries, storage, or subscriptions.
Add the selling price for one unit and then enter all meaningful variable costs tied to each sale.
Include fees carefully. Payment and marketplace percentages can materially change the contribution margin on lower priced products.
Estimate returns realistically. A higher return rate or larger loss per return increases your expected cost per sold unit.
Use the target profit field to see how many units you need beyond break even to hit a desired earnings level.
After submission, review the result cards above the form and use the export buttons to save the output as CSV or PDF.
FAQs
1. What does break even in units mean?
It is the number of units you must sell so total contribution covers all fixed costs. At that point, profit is zero and losses stop.
2. Why are payment and marketplace fees included?
They reduce the money left from each sale. Ignoring them can overstate contribution margin and make break even results appear too optimistic.
3. Should ad cost be fixed or variable?
Use ad cost per unit when acquisition spend scales with orders. Use fixed costs for monthly retainers, tools, or campaigns not tied to each unit.
4. How does the return rate affect results?
Returns increase expected cost per unit sold. A higher return rate lowers contribution margin, which means you must sell more units to break even.
5. Why is the break even unit count rounded up?
You usually cannot sell part of a product. Rounding up gives the first whole unit count that fully covers fixed costs.
6. Can I use this for bundles or subscriptions?
Yes. Enter the average selling price and average variable cost for one bundle or subscription unit during the period you are analyzing.
7. What period should fixed costs represent?
Use one consistent period, such as a month or quarter. All inputs and interpretation should match that same time frame.
8. What if contribution margin becomes negative?
Your current unit economics cannot reach break even. You need a higher selling price, lower variable costs, or both before profitability is possible.