This calculator is for anyone who needs to know how many units a store has to sell before it stops costing money: the founder validating a product idea, the operator adding a monthly tool to the stack, the seller weighing a move onto a marketplace. Enter monthly fixed costs, a unit price and a unit variable cost, and it returns contribution per unit, contribution margin, and the units and revenue needed to break even.
The trap in ecommerce is that the variable cost line hides more than product cost. Payment processing takes its cut on every order, marketplace commissions can take a mid-teens slice of the price before anything ships, and if every sale is bought with ads, customer acquisition cost is effectively a variable cost too. Returns quietly do the same damage from the other side: a percentage of units that generate full costs and no kept revenue, which raises the true cost of every unit that stays sold.
Load those into the variable cost field and the break-even number often doubles compared to the naive product-cost-only version. Better to meet that number in a calculator than three months into a launch.
Break-even calculator
Break-even is the point where total contribution covers your fixed costs. Every unit sold beyond it is profit.
Enter your monthly fixed costs, the price you sell one unit for and the variable cost of making and delivering that unit. The tool returns the contribution each unit makes, your contribution margin, and how many units and how much revenue you need to cover fixed costs. Everything runs in your browser, so nothing you enter is stored or sent anywhere.
How this is calculated
contribution_per_unit = price - variable_cost
contribution_margin_% = (price - variable_cost) / price * 100
break_even_units = fixed_costs / contribution_per_unit
break_even_revenue = break_even_units * priceContribution per unit is what is left from each sale after variable costs, and it is the money that pays down your fixed costs. Fixed costs are the ones that do not move with volume, such as rent, software and salaries. Variable costs move with each unit, such as product cost, shipping and payment fees.
Once total contribution equals fixed costs you are at break-even, and every unit after that drops straight to profit. If the contribution per unit is zero or negative the price never covers the variable cost, so break-even is not reachable at any volume and the price or cost has to change.
Worked example: fixed costs are 2000.00 a month, price is 50.00 and variable cost is 30.00. Contribution is 20.00 per unit, or a 40 percent contribution margin. You need 100 units, or 5000.00 in revenue, to break even for the month.
How to read the result
Translate break-even units into orders per day and compare that against what your traffic can plausibly convert. One hundred units a month is roughly three or four orders a day; at a typical low-single-digit conversion rate that implies a level of daily traffic you can sanity-check against reality in seconds. If the required traffic is fantasy, the model, not the marketing, is what needs to change.
Then stress-test it. Add your expected return rate to the variable cost, add per-order CAC if growth depends on paid ads, and watch the break-even move. A model that only works with zero returns and free traffic is not a plan. The gap between break-even and your realistic volume is your safety margin, and it is also the budget from which every new fixed cost, another app subscription, a VA, a warehouse shelf, must be justified.
Benchmarks: what a healthy setup looks like
As working rules of thumb: contribution margins in the 30 to 50 percent range are common for viable ecommerce products once payment fees and marketplace commissions are counted, and operators tend to get nervous when break-even eats most of their realistic monthly volume. A common informal target is reaching break-even within roughly the first two thirds of expected monthly sales, leaving the rest as profit and shock absorber for slow weeks and seasonal dips.
Keep fixed costs honest as the store grows. Ecommerce fixed costs creep in small monthly increments, an app here, a tool there, and each one silently raises the units you must sell before earning anything. Marketplace sellers should run this calculator per channel, because a mid-teens commission turns the same product into a different business on different platforms.
Frequently asked questions
What is the difference between break-even units and break-even revenue?
Break-even units is how many items you must sell to cover fixed costs. Break-even revenue is those units multiplied by price, so it is the sales total you need in the same period. Both describe the same point in different terms.
What counts as a fixed cost versus a variable cost?
The definitions are in the section above; the hard part is the gray areas. Ad spend behaves as a variable cost when every order is bought with ads, so treat per-order CAC as variable in that case. Marketplace commissions are variable because they scale with each sale, while the monthly seller subscription behind them is fixed. Returns are best handled by adding their expected cost onto the variable cost of the units that stay sold.
Why does my break-even feel too high?
A high break-even usually means either fixed costs are heavy or contribution per unit is thin. Raising price, cutting variable cost or trimming fixed overhead all pull the break-even down. Try each in the tool to see which moves it most.
Does break-even include profit?
No. Break-even is the point where you make zero profit and zero loss. To plan for a target profit, add that profit to your fixed costs before dividing by contribution per unit, and the result is the volume that hits your goal.
Verdict
Run this with fully loaded variable costs, including fees, expected returns and per-order CAC where ads drive sales, and treat the resulting unit count as the bar every new fixed cost has to clear. Platform subscriptions are usually the biggest fixed line for a small store, and our ecommerce platforms ranking compares what each stack really adds to that column. To track actual volume against your break-even month to month, the tools in our ecommerce analytics roundup do the watching for you.
