Leaf Spring Manufacturing Break-Even Analysis: $120K Monthly Revenue

Fixed costs $85.4K/mo Lease and payroll base

Contribution margin 69.8% After variable costs

Break-even revenue $122.4K/mo Monthly sales target

Break-even timing Month 2 Positive cash flow

Break-even calculator

Test monthly revenue, variable expenses, and fixed monthly costs against break-even for a leaf spring plant.

Lean Base Full

Monthly revenue Revenue is the top line that covers direct costs and plant overhead. $ Low sales High sales Variable expenses Use steel, labor, freight, commissions, and test spend that move with sales. $ Low costs High costs

Money available to cover fixed costs $305,000 $437,000 revenue - $132,000 variable expenses

Margin ratio

70%

Covers fixed costs

Yes

Fixed monthly costs Use monthly lease, utilities, software, insurance, and salaried staff. $ Lean base Full base

Break-even chart Revenue Total costs

Which leaf spring plant expenses stay fixed, and which move with sales?

Cost classification

Break-even is only useful if fixed overhead stays separate from unit-level spend. Treating steel, labor, and freight like overhead hides margin pressure and makes the Month 2 break-even look safer than it is.

Expense	Cost	Break-Even Treatment	Common Mistake
Manufacturing Facility Lease	Fixed	Include $18,500 per month in fixed overhead for the operating range.	Allocating rent into each spring and double-counting overhead.
Liability and Property Insurance	Fixed	Include $3,800 per month before calculating contribution margin.	Scaling insurance with sales volume without a policy trigger.
ERP and Inventory Software	Fixed	Include $1,400 per month as recurring operating overhead.	Treating the base system fee like a per-unit charge.
Salaried Management and Admin Payroll	Semi-fixed	Use about $48,500 per month in first-year salary load, then step up when planned headcount rises.	Modeling all payroll as if it moves one-for-one with units.
US Grade Steel	Variable	Apply the product-level steel input, from $20 to $70 per unit, to each unit sold.	Treating direct steel as overhead, which hides margin pressure.
Direct Forging Labor	Variable	Apply the per-unit labor input, from $8 to $25 per unit, inside contribution margin.	Blending production labor into fixed payroll.
Industrial Utilities and Heat Treatment Energy	Semi-variable	Use the $6,200 monthly utility base, plus $4 to $12 per unit for heat treatment energy.	Ignoring the usage-linked energy tied to furnace output.
Logistics, Freight, and Sales Commissions	Variable	Apply freight at 4.5% of first-year revenue and commissions at 2.0% of revenue.	Putting selling and shipping fees into fixed overhead.

How does break-even change from lean to full production for a leaf spring plant?

Scenario table

As production rises, fixed plant costs get spread across more sales, so break-even pressure eases. The lean case is closest to the edge, while the base and full cases carry more cushion if volume holds.

Planning assumptions only; product mix, scrap, and freight can move these results.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean Year 1 output	$437K	$101K	$85K	77.0%	$251K	Clears about $111K monthly break-even, but the cushion is still sensitive to scrap.
Base Year 3 output	$884K	$190K	$85K	78.5%	$609K	About $109K monthly break-even, with stronger fixed-cost absorption.
Full Year 5 output	$1.535M	$307K	$103K	80.0%	$1.125M	About $129K monthly break-even, with the widest cushion in this set.

What breaks the break-even plan if demand slips or steel costs spike?

Stress test

Year 1 still clears break-even, but the cushion gets thin if demand slips, fixed costs rise, or steel costs jump. Slow orders are the first warning sign.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change to Year 1 volume or cost base.	$120K	$317K cushion	Comfortable start, but volume still matters.
Revenue shortfall	Year 1 average monthly revenue falls 20% to about $350K.	$120K	$230K cushion	Demand loss cuts the slack fast.
Fixed-cost pressure	Monthly fixed costs rise 10% from about $85K to $94K.	$131K	$306K cushion	Overhead inflation lifts the floor.
Margin pressure	Steel cost rises 20% on the Year 1 steel base of about $512K a year.	$129K	$308K cushion	Raw material inflation hits every unit.
Combined pressure	Demand falls 20%, fixed costs rise 10%, and steel rises 20%.	$140K	$210K cushion	Still above break-even, but the launch cushion is much thinner.

Can this leaf spring plant clear break-even before you sign the lease and buy machinery?

Founder checklist

Confirm the monthly order book, unit price, and cost quotes before you lock the lease and equipment. The plant only clears break-even if Year 1 sales hold near $421 per unit, fixed cash burn stays near $85.4K a month, and you keep $625K minimum cash by Month 2.

1Launch demand$120K/mo

Verify the pipeline can support at least $120K in monthly revenue before you commit, because weak demand makes the fixed plant load hard to absorb.

2Blended price$421/unit

Check the Year 1 product mix against this blended selling price, because discounts or mix shifts below it will cut revenue even if unit volume holds.

3Contribution margin77% CM

Reconfirm steel, coating, packaging, heat treatment, and freight quotes; helper kits run near $36 per unit and custom forged main leaves near $118, so the Year 1 margin needs to stay around 77%.

4Fixed load$85.4K/mo

Lock lease math at $18.5K a month and Year 1 payroll at $48.5K a month, then add utilities, insurance, ERP, marketing, and testing so fixed burn does not outrun ramp.

5Cash floor$625K

Protect at least $625K in minimum cash by Month 2, because capex totals about $1.48M and the plant must survive buildout before volume covers the burn.

6QA ramp3 FTE

Make sure the fatigue rig, testing spend, and QA staffing are ready before the zinc coating line comes online in Month 4-8, or scrap and rework will eat the margin.