Aquarium Maintenance Service Break-Even: $35k Monthly Revenue

Fixed costs $25.5K/mo Fixed base

Contribution margin 72% After variable spend

Break-even revenue $35.4K/mo Needed to break even

Break-even timing Month 18 Model break-even

Break-even calculator

Use this calculator to see whether monthly revenue covers variable expenses and fixed costs.

Lean Base Full

Monthly revenue Revenue is the top line that funds fixed costs after variable expenses. $ Low sales High sales Variable expenses These are direct costs that rise with each service month, like supplies, fuel, and ad spend. $ Low costs High costs

Money available to cover fixed costs $13,150 $18,264 revenue - $5,114 variable expenses

Margin ratio

72%

Covers fixed costs

$12,333 short

Fixed monthly costs These are the monthly costs you pay even when bookings slow down. $ Low overhead High overhead

Break-even chart Revenue Total costs

Which expenses are fixed and which move with sales in an aquarium maintenance business?

Cost classification

Separate stable overhead from costs that rise with service revenue before you trust the Month 18 break-even. Revenue left after variable costs, called contribution margin, must cover fixed overhead and step-up payroll, not one-time launch capex.

Expense	Cost	Break-Even Treatment	Common Mistake
Office, admin, software, communications, and base fleet overhead	Fixed	Use $3,400 per month: rent, insurance, CRM, utilities, hosting, legal, phones, and base vehicle insurance.	Adding $138k launch capex to monthly break-even instead of cash runway.
Founder CEO, lead technician, technicians, and scheduling coordinator payroll	Semi-fixed	Use about $22.1k per month in the first year: $265k annual payroll divided by 12.	Treating payroll as fully variable when hiring changes in FTE blocks.
Aquarium Supplies & Consumables	Variable	Deduct 12% of first-year revenue before calculating contribution margin.	Budgeting supplies as a flat monthly amount while service volume grows.
Specialized Equipment & Parts	Variable	Deduct 3% of first-year revenue for parts used on customer jobs.	Classifying every tool purchase as operating break-even expense.
Service Vehicle Fuel & Maintenance	Variable	Deduct 8% of first-year revenue because route volume drives usage.	Ignoring route density, which can make fuel spend rise faster than sales.
Digital Marketing Spend	Variable	Deduct 5% of first-year revenue when modeling break-even contribution.	Counting both the annual marketing budget and the revenue percentage twice.

How does break-even change as route density moves from lean to full?

Scenario table

More route density spreads the same truck, software, and office base over more billable work, so break-even moves faster than revenue alone. In this model, the lean case still loses money, the base case turns positive, and the full case has a wide cushion.

Planning assumptions only; actual results can move with route density, pricing mix, and fuel costs.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean Year 1 route	$183k	$52k	$255k	71.6%	-$123k	Still below break-even, so monthly loss stays wide.
Base Year 2 route	$591k	$153k	$372k	74.1%	$67k	Moves above break-even and starts building cushion.
Full Year 3 route	$1.237M	$291k	$501k	76.5%	$446k	Well above break-even, with strong room for shocks.

What breaks the aquarium maintenance break-even plan first?

Stress test

Year 2 has a real cushion, but it narrows fast if recurring revenue slips or route and supply costs rise. A combined hit on revenue, margins, and fixed costs pushes the model about $41k below break-even.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change.	$501,000	$90,000 cushion	The base plan clears break-even, but the buffer is not huge.
Revenue shortfall	Revenue falls 10% from the Year 2 base.	$501,000	$30,900 cushion	Still above break-even, but a small drop cuts the cushion hard.
Fixed-cost increase	Fixed costs rise 10% above the Year 2 base.	$551,800	$39,200 cushion	Overhead creep eats the buffer even if sales hold steady.
Margin pressure	Variable expenses rise 5 percentage points.	$537,600	$53,400 cushion	Route, fuel, and supply pressure take a fast bite out of profit.
Combined pressure	Revenue falls 10%, variable expenses rise 5 points, and fixed costs rise 10%.	$591,300	$59,400 gap	This mix pushes the plan below break-even and flips profit negative.

Is this aquarium maintenance service ready for another vehicle and hire?

Founder checklist

Only if signed recurring work is close to break-even, routes stay tight, and cash covers the Month 18 dip. The model can’t carry extra vehicles or hires early; if bookings lag, fixed payroll and fleet costs outrun contribution fast.

1Launch demand$15K / $250 CAC

Check that the Year 1 marketing budget and CAC can bring in enough signed work to fill the first routes before the payroll base starts.

2Signed book173 clients

Confirm recurring contracts are near the 173-client break-even need before buying more vehicles, because empty routes do not fund the base team.

3Staff load$25.5K/mo

Year 1 payroll plus overhead is about $25.5K a month, so delay extra hires until current contribution covers that fixed base.

4Contribution72% CM

Verify the service mix really holds about 72% contribution after supplies, equipment, fuel, and digital spend, because any slip pushes break-even out.

5Route density8% revenue

Keep routes tight enough to hold fuel and maintenance near 8% of revenue in Year 1, since spread-out visits eat the margin needed for fleet growth.

6Cash runway$617K

Hold at least $617K in cash through Month 18, because that is the low point and the break-even month in the model.