Add up delivery costs and overhead, choose a margin, then check how many sales you need. Start with repair orders, parts invoices and technician time logs. Each example below uses hypothetical values you can replace.
Which calculator should you use?
| Tool | What it answers | What to check |
|---|---|---|
| Target Margin Quote | Find a quote that retains the chosen margin after revenue-based commission. | Adding a commission percentage to cost does not preserve the target margin. Commission is based on the selling price. |
| Contribution per Sale | Find the amount a completed sale contributes toward fixed costs. | Contribution still needs to cover rent, management, software, and other fixed costs before there is net profit. |
These tools answer different questions and may use different units. Choose the tool that measures what you need; a larger result does not necessarily mean a better outcome.
Target Margin Quote
Find a quote that retains the chosen margin after revenue-based commission.
Quote = (itemised delivery costs + allocated overhead) ÷ (1 − margin − commission)
Show example inputs and result
| Consumables cost | 200 |
|---|---|
| Technician hours cost | 150 |
| Bay occupancy cost | 50 |
| Fixed overhead allocated to this detail package | 100 |
| Target margin after commission | 25 % |
| Selling-price commission | 5 % |
Result: 714.2857 . Delivery cost 400; allocated overhead 100; commission 35.7143; retained contribution after assigned costs 178.5714.
Adding a commission percentage to cost does not preserve the target margin. Commission is based on the selling price.
Open target margin quoteContribution per Sale
Find the amount a completed sale contributes toward fixed costs.
Contribution = price − materials − hours × labour cost − other variable cost
Show example inputs and result
| Revenue per detail package | 800 |
|---|---|
| Materials or purchased services | 250 |
| Delivery labour hours | 5 |
| Burdened hourly labour cost | 35 |
| Other variable cost | 50 |
Result: 325 .
Contribution still needs to cover rent, management, software, and other fixed costs before there is net profit.
Open contribution per saleUse the results in your plan
For a auto detailing business, review consumables, technician hours, and bay occupancy across the complete workflow. Use one consistent period and delivery unit: a detail package. Compare the assumptions with recorded outcomes after delivery, then update the estimate.
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