Roller Coaster Engineering Design Break-Even Analysis: $80K/Month

Fixed costs $72.1K/mo Run-rate base

Contribution margin 79.1% After variable costs

Break-even revenue $91.1K/mo Monthly target

Break-even timing Month 17 Model break-even

Break-even calculator

Use this calculator to test monthly revenue, variable expenses, and fixed costs against break-even for a roller coaster engineering design firm.

Lean Base Full

Monthly revenue Top-line revenue funds design work and project delivery before overhead. $ Early stage Mature stage Variable expenses Direct costs that rise with sales, mainly travel and subcontracting. $ Low spend Heavy spend

Money available to cover fixed costs $192,131 $209,750 revenue - $17,619 variable expenses

Margin ratio

92%

Covers fixed costs

Yes

Fixed monthly costs Payroll and overhead the margin must cover each month. $ Lean team Larger team

Break-even chart Revenue Total costs

Which ride design expenses are fixed, and which move with sales?

Cost classification

Your Month 17 break-even only holds if fixed overhead stays separate from revenue-linked work. Treat safety certification and project usage as sales-linked, but keep rent, insurance, legal, IT, and base payroll in the monthly nut.

Expense	Cost	Break-Even Treatment	Common Mistake
Office Rent and Utilities ($12,000/month)	Fixed	Include the full $12,000 in monthly fixed overhead before testing margin.	Spreading rent as a revenue percentage.
Professional Liability Insurance ($3,500/month)	Fixed	Carry it as a stable monthly obligation across the planning range.	Dropping coverage in slow months to force break-even.
Accounting and Legal Services ($2,500/month)	Fixed	Model the $2,500 as recurring overhead needed to operate safely.	Treating routine compliance work as optional project spend.
IT Infrastructure and Security ($1,800/month)	Fixed	Keep it in fixed overhead because the office needs it before new work arrives.	Moving core security tools into project-only budgets.
Base Engineering Payroll ($392,500 first-year salary load)	Fixed	Here’s the quick math: $185,000 plus $145,000 plus 0.5 FTE at $125,000 equals $392,500, or about $32,708/month.	Counting all engineering payroll as variable labor.
Third-Party Safety Certification Costs (8.5% of first-year revenue)	Variable	Deduct it from revenue before calculating contribution margin, since it scales with project volume.	Parking certification fees in fixed overhead.
CAD Software Licensing and Computing Costs (4.2% of first-year revenue)	Semi-variable	Split base licenses from usage-heavy computing tied to active design and simulation work.	Treating every software dollar as fixed office overhead.
Capacity Hiring: Project Manager, CAD Specialist, or Junior Engineer	Semi-fixed	Add these salaries in steps when backlog justifies capacity, not with each new sale.	Loading construction, fabrication, or prototype budgets into design-office overhead.

How does break-even move from a lean launch to base case and full capacity?

Scenario table

Lean work leaves fixed payroll and overhead too heavy, so EBITDA stays negative. As award flow and utilization improve, contribution margin covers more of the team and break-even shows up sooner.

Scenario figures are planning assumptions, not guarantees; project awards, scope, and utilization can move the timing.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean launch	$57.4k	$13.2k	$66.7k	77.0%	-$22.5k	Still below break-even and cash negative.
Base case	$125.3k	$26.2k	$89.4k	79.1%	$9.8k	Break-even lands around Month 17.
Full-capacity buildout	$488.2k	$81.5k	$156.7k	83.3%	$249.9k	Break-even cushion widens, but award timing still drives pace.

What breaks first if awards slip or costs rise?

Stress test

By Month 17, the base plan clears break-even, but the cushion is thin. A 10% revenue miss, a 10% overhead bump, or a 5-point margin drop can wipe out most of it; combined pressure turns it into a monthly gap.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change in revenue or cost assumptions.	$1,011,000	$242,000 cushion	Base case clears break-even, but the cushion is not large.
Revenue shortfall	Monthly revenue falls 10% from the base plan.	$1,011,000	$117,000 cushion	Delayed awards cut the cushion fast, even before cost inflation shows up.
Fixed-cost pressure	Fixed costs rise 10% from the base plan.	$1,113,000	$140,000 cushion	Overhead growth pushes the break-even floor higher.
Margin pressure	Variable expenses rise 5 points and margin drops to 74.1%.	$1,080,000	$173,000 cushion	Software renewals, insurance hikes, or weak change-order control can squeeze margin.
Combined pressure	Revenue falls 15%, variable expenses rise 3 points, and fixed costs rise 10%.	$1,134,000	$69,000 gap	Delayed awards plus fee pressure create a monthly operating gap.

Can you prove the project pipeline and hourly rates before you lock in the full engineering build?

Founder checklist

Before you lock in office rent, full-time hires, and the software stack, prove the pipeline can carry Year 1 work at $175 to $325 per hour. The model does not reach breakeven until Month 17, and cash bottoms at $97K then, so the first commitment has to protect runway.

1Project pipelineYear 1 $689K

Confirm signed or near-signed projects can fill the first-year revenue plan before you add more staff.

2Billable rates$175-$325/hr

Verify buyers accept the Year 1 hourly rates by service line, or the revenue plan will slip fast.

3Office load$22.7K/mo

Test a lean or remote setup before long office commitments, because fixed overhead starts high on day one.

4Margin mix77% CM

Keep safety certification, CAD, travel, and subcontracting near plan so each billed hour keeps about 77% before fixed costs.

5Year 1 team2.5 FTE

Do not hire past the principal engineer, senior structural engineer, and 0.5 FTE mechanical design engineer until demand is repeatable.

6Cash floorM17 / $97K

Keep cash through the Month 17 trough and treat the $545K capex build as separate from operating breakeven.