B2B E-Commerce Break-Even Analysis: $867K Monthly Sales

Fixed costs $10.5K monthly base costs

Contribution margin 89.5% after variable costs

Break-even revenue $11.7K monthly target

Break-even timing Month 22 model breakeven

Break-even calculator

Use this to test whether monthly revenue covers variable expenses and still leaves enough to pay fixed monthly costs.

Lean Base Full

Monthly revenue Revenue is the pool that pays direct costs and supports fixed overhead. $ Early stage Scaled stage Variable expenses These rise with sales, such as ad spend, support, and transaction costs. $ Tighter costs Heavier costs

Money available to cover fixed costs $233,000 $260,000 revenue - $27,000 variable expenses

Margin ratio

90%

Covers fixed costs

Yes

Fixed monthly costs This is the cost base monthly contribution margin must cover. $ Lean team Larger team

Break-even chart Revenue Total costs

Which expenses stay fixed and which move with sales in a B2B e-commerce break-even model?

Cost classification

Break-even is only as reliable as the cost labels behind it. Fixed overhead runs before orders arrive, while revenue-linked fees like 2.0% transaction processing and 4.0% non-CAC ads move with sales.

Expense	Cost	Break-Even Treatment	Common Mistake
Office Rent	Fixed	Count $3,000 every month from Month 1 to Month 60 before contribution margin.	Tying rent to order volume instead of treating it as monthly overhead.
Platform Maintenance	Fixed	Include $2,500 per month as baseline operating overhead.	Blending it with transactional hosting and hiding usage pressure.
Software Licensing	Fixed	Use $1,500 per month across the planning period.	Dropping it after launch even though it recurs monthly.
Business Verification Services	Fixed	Model $800 per month as required trust and compliance overhead.	Treating verification as a one-time setup item.
Transaction Processing Fees	Variable	Apply 2.0% of revenue in the first year, stepping down to 1.6% by the mature year.	Entering 20% instead of 2.0%, which overstates fees by 10x.
Cloud Hosting (transactional)	Variable	Apply 1.5% of revenue in the first year, falling to 1.1% by the mature year.	Modeling all hosting as fixed and missing usage-linked load.
Digital Advertising Spend (non-CAC)	Variable	Apply 4.0% of revenue in the first year, declining to 3.2% by the mature year.	Combining this with seller CAC and buyer CAC budgets.
Payroll for support and admin hires	Semi-fixed	Add payroll in steps: support and admin staffing begins after the first year.	Treating payroll as one smooth percentage of sales.

How does break-even shift from a lean launch to base and full scale in B2B e-commerce?

Scenario table

Annual acquisition spend rises from $125K to $700K, while seller acquisition cost eases from $1,000 to $800 and buyer acquisition cost from $150 to $100. That changes how much revenue you need to cover the bigger fixed team and platform cost base.

Planning cases only; these scenario figures are model assumptions, not a guarantee.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean marketplace build	$867K	$91K	$776K	89.5%	$0	Lowest hurdle, but the margin cushion is thin if acquisition runs hot.
Base marketplace build	$1.25M	$125K	$1.13M	90.1%	$0	Break-even is still tight, so catalog depth and CAC control matter.
Full marketplace build	$1.70M	$158K	$1.54M	90.7%	$0	Highest revenue target, but it gives the widest cushion if sales motion scales.

What breaks this B2B e-commerce break-even plan?

Stress test

Here’s the quick math: a 15% revenue drop leaves a $130K gap, a 10% fixed-cost bump adds $51K to break-even, and variable-cost pressure pushes the target to about $954K. CAC inflation, a slower pipeline, lower order frequency, and heavier support load are the watchouts.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change in revenue, fixed costs, or variable expenses.	$867K	$0 gap	Any CAC spike or slower close rate breaks the plan.
Revenue shortfall	Revenue falls 15% from the base case.	$867K	$130K gap	A slower pipeline creates a six-figure hole fast.
Fixed-cost pressure	Fixed costs rise 10% above plan.	$918K	$51K gap	Extra overhead means the current run rate no longer covers costs.
Margin pressure	Variable expenses rise to 155% of revenue.	$954K	$87K gap	Higher support and processing costs squeeze margin fast.
Combined pressure	Revenue falls 15%, variable expenses rise to 155%, and fixed costs rise 10%.	$1.01M	$143K gap	At this level, the model runs about a $231K monthly loss.

Can this B2B marketplace prove demand before the first big spend?

Founder checklist

Before you commit to platform build, inventory, and hires, prove both seller and buyer acquisition works at or below the model CACs. The model only breaks even in Month 22, and cash bottoms at -$412K in Month 21, so weak traction turns into a runway problem fast.

1Seller CAC$1,000

Verify seller acquisition holds at or below $1,000 before you scale the $50K Year 1 seller marketing budget, or supply gets expensive before orders can pay back the spend.

2Buyer CAC$150

Verify buyer acquisition stays at or below $150 before you scale the $75K Year 1 buyer marketing budget, because weak buyer flow keeps order volume below break-even.

3Fixed Burn$67.2K/mo

Verify Year 1 salaries plus fixed overhead stay near $67.2K per month, since that is the burn you must carry until Month 22 break-even.

4Order Take$2 + 3.0%

Verify each order really earns the $2 fixed commission plus 3.0% of order value, because that spread has to cover processing, hosting, support, and sales costs.

5Launch Ramp250/180/120

Test the Year 1 repeat-order targets of 250 small business, 180 mid-market, and 120 enterprise orders before adding the Month 13 support and admin hires, or headcount will outrun revenue.

6Cash Cushion-$412K

Verify you can fund the Month 21 cash low of -$412K, because the runway has to survive the gap before break-even arrives in Month 22.