Carbon Monoxide Testing Service Break-Even: About $27K/Month

Fixed costs $19.2K/mo Overhead + base labor

Contribution margin 72% After variable costs

Break-even revenue $26.7K/mo Monthly target

Break-even timing Month 5 Launch ramp

Break-even calculator

Use this calculator to test monthly revenue against variable expenses and fixed monthly costs for a carbon monoxide testing service.

Lean Base Full

Monthly revenue Revenue sets the pool that has to cover direct costs and fixed overhead. $ Low volume High volume Variable expenses Use direct costs that rise with each job, including consumables, parts, fuel, and card fees. $ Light direct cost Heavy direct cost

Money available to cover fixed costs $69,050 $94,333 revenue - $25,283 variable expenses

Margin ratio

73%

Covers fixed costs

Yes

Fixed monthly costs This is the monthly cost base that margin must cover before profit starts. $ Small overhead Large overhead

Break-even chart Revenue Total costs

Which expenses stay fixed and which move with sales in a carbon monoxide testing service?

Cost classification

Break-even is only useful if each expense behaves the way the model says it does. Misclassifying detector hardware, fuel, or card fees as fixed will overstate margin as bookings grow.

Expense	Cost	Break-Even Treatment	Common Mistake
Small Office Lease	Fixed	Hold at $2,200/month across the normal planning range.	Spreading rent per job and making break-even look better at low volume.
Insurance Premiums Liability	Fixed	Use $850/month as recurring overhead before contribution margin.	Treating insurance as job-level when it does not rise with each booking.
Scheduling and CRM Software	Fixed	Carry $350/month as a stable operating platform expense.	Ignoring it because it is small, which understates monthly overhead.
Equipment Consumables and Calibration	Variable	Model at 8% of first-year revenue, falling to 6% by the mature year.	Classifying calibration supplies as fixed even though usage follows inspections.
Hardware Parts and Detectors	Variable	Model at 12% of first-year revenue, falling to 10% by the mature year.	Forgetting detector hardware rises when installation bookings rise.
Fuel and Vehicle Maintenance	Variable	Use 5% of first-year revenue, declining to 4.2% as routing improves.	Budgeting one flat vehicle amount while route count and mileage grow.
Lead Safety Technician	Semi-fixed	Add capacity in hiring steps: $55,000/year per full-time technician.	Assuming payroll rises smoothly instead of stepping up when capacity is added.
Online Marketing Spend	Semi-variable	Start with a $25,000 first-year budget and track CAC at $85 per customer.	Treating marketing as fully fixed while lead flow and bookings depend on spend efficiency.

How does break-even shift across lean, base, and full booking cases for a carbon monoxide testing service?

Scenario table

Break-even improves as revenue per month rises faster than variable spend, but fixed overhead still has to be covered every month. The key risk is not revenue alone; it’s keeping enough booked jobs to hold utilization steady.

These are planning assumptions from the model, not a guarantee of future results.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean founder-led launch	$45.6k	$12.8k	$22.7k	72.0%	$10.2k	Thin cushion, so missed bookings can erase profit.
Base local referral mix	$94.3k	$25.3k	$39.3k	73.2%	$29.8k	Clearer cushion, but steady referrals still matter.
Full route-density scale	$137.4k	$35.2k	$51.3k	74.4%	$50.9k	Strong cushion, if routes stay full and efficient.

What breaks the break-even plan for a carbon monoxide testing service?

Stress test

The base plan has a cushion, but it gets thin fast if bookings slip, travel time rises, or overhead creeps up. Weak add-on conversion, CAC above $85, and hiring before repeatable bookings are the main break-even risks.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change.	$268k	$188k cushion	Healthy cushion, but bookings still need to hold.
Revenue shortfall	Revenue is 20% lower at about $365k.	$268k	$97k cushion	A softer booking month still clears break-even.
Fixed-cost pressure	Fixed costs rise by $2k a month.	$296k	$160k cushion	More overhead cuts the room for error fast.
Margin pressure	Variable expenses rise from 28% to 33% of revenue.	$288k	$168k cushion	A 5-point margin slip removes about $23k of contribution.
Combined pressure	Revenue is 40% lower at about $274k, variable expenses rise to 33%, and fixed costs rise by $2k a month.	$304k	$30k gap	Weak add-ons, long drives, or CAC above $85 can tip this into loss.

What should you verify before you commit to vehicles, tools, payroll, and paid leads?

Founder checklist

Yes, but only if the service scope is clear, the Month 2 cash trough is funded, and paid leads can land at or below the $85 Year 1 CAC. Delay the second vehicle and extra payroll until route density and booked jobs make break-even believable.

1Scope GateLaunch month

Confirm the inspection scope and any certification path before you buy analyzers and low-level monitoring kits, so the first spend supports a sellable service.

2Fixed Load$4,650/mo

Check that liability insurance stays near the $850/month plan and the rest of the lease, software, utilities, dues, and admin overhead stays flat enough for break-even.

3Unit Margin72.0%

Test whether Year 1 pricing at $125, $110, and $95 still clears the 8% consumables, 12% hardware, 5% fuel, and 3% processing load, with detector placement really hitting 40% and maintenance 10%.

4Payroll Ramp$175K

Do not add the $48k sales liaison or the junior field technician until booked jobs can cover Year 1 payroll, which starts at about $175K from the current FTE plan.

5Cash Floor$822K

Keep enough reserve to absorb the Month 2 cash low and still fund the path to Month 5 break-even, because the first months carry the capex and hiring load.

6CAC Test$85

Track paid lead cost against the Year 1 target and do not scale ads until scheduling, CRM, dispatch, calibration logs, and follow-up are working, and route density supports the $32k second vehicle.