Base Isolation Engineering Break-Even Plan: $135K Monthly Revenue

Fixed costs $93.4K/mo Monthly overhead base

Contribution margin 72% After variable costs

Break-even revenue $129.7K/mo Revenue needed monthly

Break-even timing Month 8 Launch ramp point

Break-even calculator

Test monthly revenue against variable expenses and fixed costs to see where this seismic engineering model covers its overhead.

Lean Base Full

Monthly revenue Revenue is the top line that must cover variable and fixed costs. $ Thin pipeline Mature pipeline Variable expenses These are direct project costs that rise with each job, like travel and outside review. $ Lean delivery Heavy delivery

Money available to cover fixed costs $325,261 $422,417 revenue - $97,156 variable expenses

Margin ratio

77%

Covers fixed costs

Yes

Fixed monthly costs These are the monthly costs the contribution margin has to cover, including staff and office overhead. $ Small team Larger team

Break-even chart Revenue Total costs

Which expenses are fixed and which move with sales for this engineering firm?

Cost classification

Break-even is reliable only when payroll, insurance, software, travel, and review fees sit in the right buckets. Put fixed items in monthly overhead and variable items as a percent of revenue, or Month 8 break-even can look earlier than it is.

Expense	Cost	Break-Even Treatment	Common Mistake
Principal Structural Engineer salary	Fixed	Include $17,500 per month in overhead based on the $210,000 annual salary.	Treating licensed payroll as project-by-project labor.
Professional Liability Insurance	Fixed	Include $6,800 per month in fixed overhead.	Leaving required coverage out of break-even overhead.
Advanced Engineering Software Subscriptions	Fixed	Include $3,200 per month in fixed overhead.	Modeling core design software as optional usage spend.
Project Specific Travel	Variable	Use 6% of first-year revenue, or $97,920 on $1,632,000.	Flat-lining site travel even as project volume rises.
External Peer Review Fees	Variable	Use 9% of first-year revenue, or $146,880 on $1,632,000.	Burying review fees in overhead instead of job margin.
Cloud Computing Infrastructure	Semi-variable	Start with the $1,500 monthly base, then add workload-driven processing as projects scale.	Ignoring simulation spikes during heavy analysis months.
Business Development Director	Semi-fixed	Add the role after the launch ramp, starting Month 13 at $150,000 annually.	Adding the full sales salary in Month 1.

How does break-even change from a lean launch to a full project pipeline?

Scenario table

Lean revenue does not cover the fixed cost load, so the launch case stays in the red. The base case gets close, but only the fuller pipeline creates a clear cushion.

Scenario figures are planning assumptions from the model, not guarantees; actual results will move with project mix, staffing, and timing.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean launch pipeline	$102k	$28.6k	$106.8k	72.0%	-$33.4k	Still below break-even; the launch book is too thin.
Base first-year plan	$136k	$38.1k	$106.8k	72.0%	-$8.9k	Near break-even, but the first-year plan still needs more signed hours.
Full Year 2 pipeline	$286k	$72.9k	$155.8k	74.5%	$57.1k	Clears break-even and leaves room for added hiring.

What breaks the break-even plan for this seismic engineering firm?

Stress test

The plan is tight. At Year 1 revenue of $1.63M, the model only has a $282k cushion over break-even, so slower project wins, higher outside review spend, or more overhead can erase the buffer fast.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change; Year 1 revenue stays at $1.632M.	$1.35M	$282k cushion	There is room, but not much if proposals slip.
Revenue shortfall	Project wins slow and revenue falls 15% from Year 1.	$1.35M	$37k cushion	A small miss nearly wipes out the buffer.
Fixed-cost increase	Fixed overhead rises 10% across office, insurance, software, and admin.	$1.48M	$147k cushion	Overhead creep tightens the break-even line fast.
Margin pressure	Outside review and other variable costs rise 5 points, cutting margin to 67%.	$1.45M	$181k cushion	More outside review work lifts the revenue needed to stay safe.
Combined pressure	Revenue falls 15%, fixed overhead rises 10%, and margin slips to 67%.	$1.60M	$208k gap	A slow sales month and cost creep can push break-even above the run rate.

What should you verify before locking in the lease and hiring plan for a seismic base isolation engineering firm?

Founder checklist

Don’t commit to major fixed spend until you can show enough signed work to support about $136K in monthly revenue, cover the $240K cash low in Month 7, and keep delivery staffed without overhiring. If those three do not line up, break-even is still fragile.

1Backlog$136K/mo

Verify signed pipeline is near Year 1 monthly revenue and comes from 4 to 5 mixed projects per month, so the first fixed-cost wave has real demand behind it.

2Fixed Load$30.9K/mo

Check the monthly overhead before you lock the office, because the lease, insurance, software, cloud, memberships, and admin support create a heavy base cost from day one.

3Contribution72% CM

Confirm the Year 1 service mix still holds a 72% contribution margin after geotechnical data, simulation, travel, and external peer review fees, since that margin funds the fixed base.

4Lead CoverageMonth 1

Keep Principal Structural Engineer coverage in place from Month 1 and only add more staff when proposal throughput proves the work is there to keep them busy.

5Cash Cushion$240K

Hold cash through Month 7 minimum cash need, because the model’s lowest balance arrives before revenue fully covers payroll, software, and operating overhead.

6Market Proof$4.5K CAC

Approve the Year 1 marketing budget only if proposal tracking shows it turns into signed work, because a $4,500 CAC is too expensive to fund without repeat referral flow.