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Production Line Unit Economics Calculator

This unit-economics model avoids dividing cost by units started when only saleable units earn revenue. It discloses first-pass yield, recovery, effective yield, utilization, cost per saleable unit, contribution before fixed cost, and period operating profit.

Units started in the production periodFirst-pass good yield (%)Rejected units recovered by rework (%)Net selling price per saleable unitMaterial cost per started unitDirect labor per started unitVariable overhead per started unitRework cost per recovered unitFixed line cost for the periodScheduled line hoursRated starts per line hour

First-pass good units-

Units rejected at first pass-

Rejected units recovered by rework-

Units scrapped after rework-

Total saleable good units-

Saleable units divided by starts-

Material, labor, and variable overhead per start-

Variable cost across all starts-

Rework cost on recovered units-

Variable, rework, and fixed line cost-

Revenue from saleable units-

Full production cost per saleable unit-

Contribution per saleable unit before fixed cost-

Sales revenue less total production cost-

Started units divided by rated schedule-

Decision view

First-pass, rework, and scrap flow

First-pass, rework, and scrap flowStarted units split into first-pass good output and rejects; rejects then split into recovered units and scrap before cost is assigned to saleable output.

Exact scenario comparisonUnits started in the production period changes while all other entered assumptions remain constant.

Units started in the production period	First-pass good units	Units rejected at first pass	Rejected units recovered by rework	Units scrapped after rework	Total saleable good units	Saleable units divided by starts	Material, labor, and variable overhead per start	Variable cost across all starts	Rework cost on recovered units	Variable, rework, and fixed line cost	Revenue from saleable units	Full production cost per saleable unit	Contribution per saleable unit before fixed cost	Sales revenue less total production cost	Started units divided by rated schedule

How to use Production Line Unit Economics Calculator

Enter starts and observed first-pass yield for one product and production period.
Enter the share of rejects recovered and the incremental cost per recovered unit.
Add start-based material, labor, overhead, fixed line cost, schedule hours, and rated speed.

Calculator guide

Understanding Production Line Unit Economics Calculator

Follow a production batch from starts to first-pass good output, rework recovery, final scrap, and saleable units. Costs are assigned on the physical basis that creates them: material, labor, and variable overhead on every start; rework cost only on recovered units; fixed line cost on the period.

Every start consumes cost Start-based variable cost includes good, reworked, and scrapped units.

Rework is incremental Recovered units add their own repair cost.

Saleable output is the denominator Full unit cost is divided by units that can earn revenue.

Utilization is separate Schedule loading is shown without pretending that higher utilization guarantees better yield.

Detailed calculation process

Reconcile physical yield with cost per saleable unit

The default starts 10,000 units at 92% first-pass yield, recovers 60% of rejects, sells good units for $18, and incurs $10.40 per start plus $2.20 per recovered unit and $32,000 fixed cost.

General formula: Q_FP = Q_0 y_FP/100Q_reject = Q_0 - Q_FPQ_rework = Q_reject r/100Q_scrap = Q_reject - Q_reworkQ_sale = Q_FP + Q_reworkC_total = Q_0(c_m + c_l + c_v) + Q_rework c_r + Fc_full = C_total / Q_saleProfit = Q_sale p - C_total Quality quantities are solved before economics. Start-based costs apply to all launched units, while rework cost applies only to recovered rejects. Fixed cost is added once for the production period.

What each symbol means

Q_0, Q_FP Units started and first-pass good units (units).

y_FP, r First-pass yield and reject recovery rates (%).

Q_rework, Q_scrap, Q_sale Recovered, scrapped, and final saleable units.

c_m, c_l, c_v, c_r Material, labor, variable overhead per start, and rework cost per recovered unit ($/unit).

F, p Fixed line cost ($/period) and net sale price ($/saleable unit).

Worked substitution with the default inputs

1. Split first-pass output Q_FP = 10,000 x 92% = 9,200Q_reject = 10,000 - 9,200 = 800 Eight hundred units enter disposition rather than saleable inventory.

2. Resolve rework and scrap Q_rework = 800 x 60% = 480Q_scrap = 800 - 480 = 320 Recovered units return to good output; the remainder is final scrap.

3. Count saleable units Q_sale = 9,200 + 480 = 9,680effective yield = 9,680/10,000 = 96.8% The denominator for full unit cost is 9,680 saleable units.

4. Build total production cost C_total = 10,000 x ($6.20 + $2.80 + $1.40) + 480 x $2.20 + $32,000 = $137,056 Base conversion, rework, and fixed cost remain traceable.

5. Reconcile unit cost and profit c_full = $137,056/9,680 = $14.16Profit = 9,680 x $18 - $137,056 = $37,184 Revenue of $174,240 less total cost equals the displayed profit.

The default batch yields 9,680 saleable units, 320 scrap units, $14.16 full cost per saleable unit, and $37,184 operating profit.

Material flow

See where the started units finish

The diagram preserves the two quality gates before showing the cost composition.

First-pass yield split Started units divide into first-pass good output and rejects before any rework recovery is credited to saleable production.

Rework-scrap branch Rejected units split again into recovered output and unrecovered scrap, keeping recovery yield visible in the material flow.

Full-cost denominator Start-based conversion cost, recovered-unit rework cost, and period fixed cost reconcile against total saleable units to produce full cost per good unit.

Worked situations

Practical examples

At 92% first-pass yield, 10,000 starts create 9,200 first-pass good units and 800 rejects.
Recovering 60% of the rejects adds 480 good units and leaves 320 units as scrap, producing 9,680 saleable units.

Better inputs

Useful tips

Use saleable good units as the output quantity and record scrap, rework, and startup loss separately.
Classify costs by how they actually behave at the modeled production level instead of labeling every overhead item fixed.
Recalculate unit economics when batch size, utilization, labor shift, or supplier pricing changes.

Before relying on the result

Limitations and common mistakes

The model assumes one rework pass and one average recovery cost.
Downtime, changeovers, work-in-process timing, warranty, inventory valuation, and overhead absorption policy are simplified.
Rated units per hour is a schedule reference and does not diagnose the bottleneck operation.

Reference

Key terms

First-pass yield: Share of started units accepted without rework.
Rework recovery: Share of first-pass rejects converted into saleable output.
Effective yield: Final saleable units divided by total units started.

Important note

Use saleable units and actual disposition records; production starts alone overstate revenue-capable output.

Frequently asked questions

Why is material charged to scrap?

Scrapped units were started and consumed the entered start-based material and conversion resources.

Does recovered output count twice?

No. It begins inside the reject quantity and is added once to final saleable output.

Should fixed cost be used in contribution per unit?

The page reports contribution before fixed cost and full cost separately to avoid mixing the two decisions.

What if rework needs several passes?

Build a routing-level rework model; one average recovery rate cannot represent repeated loops.