Online Marketplace Store Break-Even: $143K Monthly Sales

Fixed costs $11.3K/mo Year-1 base

Contribution margin 82% After variable costs

Break-even revenue $13.8K/mo Cover fixed base

Break-even timing Month 25 Model ramp

Break-even calculator

Test how monthly sales, variable costs, and fixed overhead work against break-even.

Lean Base Full

Monthly revenue Use monthly sales before variable costs; it sets the margin that pays overhead. $ Small sales Big sales Variable expenses Include fees, shipping, and direct inventory costs that rise with each sale. $ Light costs Heavy costs

Money available to cover fixed costs $38,115 $45,000 revenue - $6,885 variable expenses

Margin ratio

85%

Covers fixed costs

Yes

Fixed monthly costs Include monthly overhead that stays on even when sales slow. $ Lean overhead Heavy overhead

Break-even chart Revenue Total costs

Which expenses are fixed, and which move with sales for an online marketplace store?

Cost classification

Break-even is only useful if order-linked expenses are kept out of fixed overhead. In the first year, 17.0% of sales runs through inventory, packaging, platform fees, and fulfillment before the store covers monthly fixed costs.

Expense	Cost	Break-Even Treatment	Common Mistake
Wholesale Inventory Cost	Variable	Use 6.0% of sales in the first year as a direct reduction to contribution margin.	Treating inventory buys as profit impact only when sold, while ignoring cash tied up before sale.
Packaging Materials	Variable	Apply 1.5% of sales in the first year because boxes, mailers, and inserts rise with orders.	Rolling packaging into general supplies and overstating contribution per order.
Platform & Transaction Fees	Variable	Model at 7.0% of sales in the first year before testing break-even volume.	Treating marketplace fees like a flat subscription and missing fee drag on each sale.
Shipping & Fulfillment Costs	Variable	Use 3.5% of sales in the first year unless part of shipping is subsidized by the store.	Counting customer-paid shipping as margin while ignoring label and fulfillment charges.
Software & Technology Subscriptions	Fixed	Include $250 per month in fixed overhead across the planning range.	Spreading the subscription across orders and hiding the sales level needed to cover it.
Annual Marketing Budget	Semi-variable	Use the $15,000 first-year budget with the $12 customer acquisition cost to test paid growth.	Calling all marketing fixed while campaign spend rises with customer targets.
Part-time Bookkeeper	Semi-fixed	Model 0.5 FTE against the $20,000 annual salary, or $10,000 per year at planned staffing.	Modeling bookkeeping as a per-order fee instead of a staffing step.

How does break-even change from a lean launch to a base store to a full team setup?

Scenario table

The lean case breaks even with less overhead, while the base and full cases need more revenue to cover added labor and marketing. Here’s the quick math: higher fixed costs raise the break-even bar even when the margin stays strong.

Planning assumptions only; traffic, category mix, returns, and fulfillment can move break-even fast.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean validation store	$143k	$26k	$118k	82.0%	-$1k	Very tight cushion; a small traffic miss can slip it below break-even.
Base repeatable store	$174k	$29k	$145k	83.4%	$0	This is the Month 25 break-even point, so repeat sales and fee control matter most.
Full team catalog	$227k	$35k	$192k	84.7%	$0	Higher payroll needs stronger demand, but it gives the best scale path if traffic holds.

What breaks this store’s break-even plan?

Stress test

The base plan is only slightly above break-even, so a 10% sales miss or a small rise in fixed or marketplace costs can flip the store into a monthly loss. Higher postage, returns, ad costs, and slower repeat buying are the main risks.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change; revenue holds at about $143K and fixed costs stay at $118K with an 82% contribution margin.	$144K	$1K gap	The plan is only barely above break-even.
Revenue shortfall	Revenue falls 10% to about $129K while the cost structure stays the same.	$144K	$12K gap	A modest sales miss quickly creates a monthly loss.
Fixed-cost increase	Fixed costs rise by $1K to $119K with revenue and margin unchanged.	$145K	$2K gap	Even small overhead creep tightens the cushion.
Margin pressure	Variable costs rise 5 points, cutting contribution margin from 82% to 77%.	$153K	$10K gap	Higher postage, returns, or ad costs push break-even up fast.
Combined pressure	Revenue slips to about $129K, fixed costs rise to $128K, and contribution margin slips to 77%.	$166K	$29K gap	One bad month can put the store far below break-even.

Can an online marketplace store clear break-even before you commit to inventory and hiring?

Founder checklist

Treat this like a go/no-go gate before you buy more inventory or add headcount. The model only works if you can hold a $38.50 weighted unit price, a $42.35 AOV, and a Month 25 break-even path while funding the Year 1 loss.

1Price Check$38.50 / $42.35

Verify the product mix really holds a $38.50 weighted unit price and a $42.35 AOV in Year 1, because weaker pricing cuts the whole break-even plan.

2Margin Stack82% CM

Confirm contribution margin stays near 82% after 6.0% inventory, 1.5% packaging, 7.0% platform fees, and 3.5% shipping, or the model loses room for wages and fixed costs.

3Fulfillment339 orders/mo

Test whether the owner, curator, and part-time bookkeeper can pick, pack, ship, and answer service on about 339 monthly orders before adding more help.

4CAC Gate$12 CAC

Keep Year 1 marketing near the $15K budget unless CAC stays around $12, since repeat buyers are only 15% of new customers in Year 1.

5Fixed Load$10.5K/mo

Verify the launch can carry about $10.5K a month of fixed payroll and overhead before growth spend, because that cost sits in the path to Month 25 break-even.

6Cash Buffer$765K

Hold the modeled $765K minimum cash, since the plan does not reach break-even until Month 25 and payback takes 35 months.