Index
What stock ROI is and why it matters more than gross margin
The stock ROI formula step-by-step
A complete example with real numbers
How ROI increases without changing the selling price
ROI by vehicle type: where the real money is
The trap of high margin with low ROI
How to use ROI to decide what to buy
Dealcar and stock ROI calculations per vehicle
Frequently Asked Questions
What stock ROI is and why it matters more than gross margin
ROI stands for Return on Investment. When applied to a dealership's stock, stock ROI measures the profit generated by every pound invested in inventory over a specific period.
The gross margin measures the absolute profit of an operation: you bought at 9,000, sold at 11,500, and made 2,500 pounds. ROI measures the efficiency of that profit in relation to the capital employed and the amount of time it was tied up.
Two deals with the same gross margin can have completely different ROIs. A car bought for £18,000 with a margin of £2,000 that takes 90 days to sell generates a much lower ROI than a car bought for £7,000 with a margin of £1,200 that sells in 20 days. The second one requires less capital, releases it quicker, and allows it to be reinvested more times in the same period.
See how to calculate gross and net margins in used cars.
A dealership managing business by gross margin might be leaving a lot of money on the table without realising, because they are choosing vehicles with high absolute margins but slow rotation and high tied-up capital.
The stock ROI formula step-by-step
Stock ROI is calculated in three steps.
First, calculate the net margin of the deal: selling price minus purchase price, minus all direct costs attributable to the vehicle (prep, admin, proportional advertising, stocking finance cost if the car was financed).
Second, divide that net margin by the capital invested in the vehicle (the purchase price plus prep costs).
Third, annualise it to be able to compare deals of different durations.
The formula is: Annualised ROI = (Net Margin / Invested Capital) x (365 / Days in stock)
The result is a percentage indicating how much that invested capital yields if we project the return obtained during the days the vehicle was in inventory over a year.
A complete example with real numbers
Take two vehicles that a dealership has in stock at the same time:
Vehicle A: Premium SUV bought at £22,000. Prep: £600. Total invested capital: £22,600. Selling price: £25,500. Financing cost (stock finance 7%, 85 days): £368. Admin cost: £120. Net margin: 25,500 - 22,000 - 600 - 368 - 120 = £2,412. Days in stock: 85.
Annualised ROI: (2,412 / 22,600) x (365 / 85) = 0.1068 x 4.29 = 45.8% annually
Vehicle B: Mid-range saloon bought at £8,500. Prep: £350. Total invested capital: £8,850. Selling price: £10,400. Financing cost (stock finance 7%, 28 days): £47. Admin cost: £120. Net margin: 10,400 - 8,500 - 350 - 47 - 120 = £1,383. Days in stock: 28.
Annualised ROI: (1,383 / 8,850) x (365 / 28) = 0.1563 x 13.04 = 203.8% annually
The SUV has a gross margin of £2,900. The saloon has a gross margin of £1,900. If you decide what to buy based on gross margin, you choose the SUV.
But the saloon generates an annualised ROI 4.5 times higher. With the same capital you have tied up in the SUV for 85 days, you could have bought and sold the saloon three times, generating approximately £4,149 of total net margin compared to £2,412 for the SUV.
How ROI increases without changing the selling price
Stock ROI depends on three variables: net margin, invested capital, and days in stock. Raising the selling price is the most obvious way to improve margin, but it is not always possible. The other two variables are more actionable.
Reducing the invested capital in each deal means buying better: getting the same car at a lower entry price. Every £500 saved on the purchase price, with the same selling price, improves the ROI of that deal. That is why sourcing at a good price is a dealership's most valuable asset from an ROI perspective.
Reducing days in stock is the lever that has the biggest impact on ROI at scale. Going from 60 days of average rotation to 35 days practically doubles the annualised ROI of the business without changing either the purchase or the selling price. That reduction comes from listing faster, adjusting prices more quickly, and having more active sales channels.
See how to calculate and control days in stock in a car dealership.
ROI by vehicle type: where the real money is
When the ROI calculation is applied by segment, the results usually surprise dealership owners who were managing by gross margin.
Cheap runarounds under £5,000 have low gross margins (between £400 and £900), but if they sell in under 15 days and the invested capital is small, the annualised ROI can be very high. The issue is that the proportional prep costs are high and the volume of sales needed to make the model profitable requires a lot of operational capacity.
Mid-range SUVs between £8,000 and £18,000 are usually the segment with the best balance between absolute margin and stock turn speed. An SUV that sells in 35 days with a net margin of £1,600 on an £11,000 capital investment generates an annualised ROI of around 150%, which is hard to beat with other vehicle profiles without taking on more risk.
Read which car brands turn over the fastest in a dealership.
Premium vehicles over £20,000 have high gross margins but slow turn. If the premium SUV takes 90 days and the mid-range one takes 30, the difference in ROI may justify having fewer expensive cars and more mid-range cars with the same amount of capital.
The trap of high margin with low ROI
The most common case of low ROI with an apparently good margin is a car that has spent too much time in stock. A vehicle bought at £16,000 with a gross margin of £2,800 that has gone 120 days unsold has an annualised ROI of approximately 53%. That same car, sold in 40 days, would have an annualised ROI of 160%.
The trap is that the dealership owner sees the £2,800 margin as a good result and doesn't calculate the opportunity cost of having £16,000 tied up for 120 days. If they had dropped the price by £500 on day 45, they would have sold quicker with a margin of £2,300 and a much higher ROI. They would have made less on that deal, but the released capital could have generated another deal with a positive margin.
The rule of thumb is: an early price reduction is almost always better than a long wait. The margin recovered by selling fast outweighs what is lost waiting for a buyer who will pay the original price.
Read also how to reduce days in stock with dynamic pricing.
How to use ROI to decide what to buy
Once you have the historical ROI by vehicle type in your own dealership, you can use it as a buying decision criterion.
The process is: before buying a car, estimate the expected net margin, the capital you are going to invest, and the days you expect it to take to sell based on the history of that vehicle type in your dealership. Calculate the expected annualised ROI. If it is lower than your average business ROI, this deal will hold back capital profitability even if the gross margin looks attractive.
Over time, this analysis allows you to identify which types of vehicles generate the most ROI in your specific market and focus your sourcing on those profiles. The result is not the same in all dealerships: it depends on the area, the sales channels, and the typical buyer profile.
See where the most efficient dealerships buy cars.
Dealcar and stock ROI calculations per vehicle
Calculating the ROI of each deal manually requires keeping a precise record of the entry cost, additional costs, and days in stock of each vehicle. Without a system, this job is tedious and most dealerships stop doing it.
From Dealcar, you can record all the costs associated with each vehicle from the moment of purchase and see the real net margin of each deal upon closing. The dashboard allows you to see the performance by vehicle type and by period, which facilitates ROI analysis without manual reporting. If you want to see how it works, request a demo at dealcar.io.
Frequently Asked Questions
What is a reasonable annualised ROI for a dealership?
It depends on the segment and business model, but as a guide: an annualised ROI below 50% indicates that the stock capital is not being very efficient. Between 80% and 150% is a reasonable range for a dealership with normal rotation. Above 150%, the business is using capital very efficiently, usually because it has good rotation and a good sourcing price.
Does stock ROI include fixed business costs?
Not in the basic calculation per vehicle. The stock ROI described in this article measures the efficiency of the capital invested in the inventory with the direct costs of each operation. The fixed costs of the business (rent, staff, tools) are included in the overall business profitability analysis, not in the ROI per vehicle.
Does it make sense to calculate ROI in a small business?
Yes, especially in small businesses where each deal weighs more on the total result. A dealer selling 8 cars a month has much more room for ROI improvement than one selling 80, because each buying decision impacts the month's result proportionally more.
How does stocking finance affect ROI?
Stocking finance reduces the equity capital invested in each vehicle (since a portion is provided by the finance company), which in principle improves ROI on equity. However, it adds a direct cost for interest that must be included in the net margin calculation. If the cost of financing is less than the benefit of releasing equity capital for more deals, stocking finance improves overall ROI. This is why stocking finance is not just a liquidity tool: properly used, it is a tool for improving ROI.
Index
What stock ROI is and why it matters more than gross margin
The stock ROI formula step-by-step
A complete example with real numbers
How ROI increases without changing the selling price
ROI by vehicle type: where the real money is
The trap of high margin with low ROI
How to use ROI to decide what to buy
Dealcar and stock ROI calculations per vehicle
Frequently Asked Questions
What stock ROI is and why it matters more than gross margin
ROI stands for Return on Investment. When applied to a dealership's stock, stock ROI measures the profit generated by every pound invested in inventory over a specific period.
The gross margin measures the absolute profit of an operation: you bought at 9,000, sold at 11,500, and made 2,500 pounds. ROI measures the efficiency of that profit in relation to the capital employed and the amount of time it was tied up.
Two deals with the same gross margin can have completely different ROIs. A car bought for £18,000 with a margin of £2,000 that takes 90 days to sell generates a much lower ROI than a car bought for £7,000 with a margin of £1,200 that sells in 20 days. The second one requires less capital, releases it quicker, and allows it to be reinvested more times in the same period.
See how to calculate gross and net margins in used cars.
A dealership managing business by gross margin might be leaving a lot of money on the table without realising, because they are choosing vehicles with high absolute margins but slow rotation and high tied-up capital.
The stock ROI formula step-by-step
Stock ROI is calculated in three steps.
First, calculate the net margin of the deal: selling price minus purchase price, minus all direct costs attributable to the vehicle (prep, admin, proportional advertising, stocking finance cost if the car was financed).
Second, divide that net margin by the capital invested in the vehicle (the purchase price plus prep costs).
Third, annualise it to be able to compare deals of different durations.
The formula is: Annualised ROI = (Net Margin / Invested Capital) x (365 / Days in stock)
The result is a percentage indicating how much that invested capital yields if we project the return obtained during the days the vehicle was in inventory over a year.
A complete example with real numbers
Take two vehicles that a dealership has in stock at the same time:
Vehicle A: Premium SUV bought at £22,000. Prep: £600. Total invested capital: £22,600. Selling price: £25,500. Financing cost (stock finance 7%, 85 days): £368. Admin cost: £120. Net margin: 25,500 - 22,000 - 600 - 368 - 120 = £2,412. Days in stock: 85.
Annualised ROI: (2,412 / 22,600) x (365 / 85) = 0.1068 x 4.29 = 45.8% annually
Vehicle B: Mid-range saloon bought at £8,500. Prep: £350. Total invested capital: £8,850. Selling price: £10,400. Financing cost (stock finance 7%, 28 days): £47. Admin cost: £120. Net margin: 10,400 - 8,500 - 350 - 47 - 120 = £1,383. Days in stock: 28.
Annualised ROI: (1,383 / 8,850) x (365 / 28) = 0.1563 x 13.04 = 203.8% annually
The SUV has a gross margin of £2,900. The saloon has a gross margin of £1,900. If you decide what to buy based on gross margin, you choose the SUV.
But the saloon generates an annualised ROI 4.5 times higher. With the same capital you have tied up in the SUV for 85 days, you could have bought and sold the saloon three times, generating approximately £4,149 of total net margin compared to £2,412 for the SUV.
How ROI increases without changing the selling price
Stock ROI depends on three variables: net margin, invested capital, and days in stock. Raising the selling price is the most obvious way to improve margin, but it is not always possible. The other two variables are more actionable.
Reducing the invested capital in each deal means buying better: getting the same car at a lower entry price. Every £500 saved on the purchase price, with the same selling price, improves the ROI of that deal. That is why sourcing at a good price is a dealership's most valuable asset from an ROI perspective.
Reducing days in stock is the lever that has the biggest impact on ROI at scale. Going from 60 days of average rotation to 35 days practically doubles the annualised ROI of the business without changing either the purchase or the selling price. That reduction comes from listing faster, adjusting prices more quickly, and having more active sales channels.
See how to calculate and control days in stock in a car dealership.
ROI by vehicle type: where the real money is
When the ROI calculation is applied by segment, the results usually surprise dealership owners who were managing by gross margin.
Cheap runarounds under £5,000 have low gross margins (between £400 and £900), but if they sell in under 15 days and the invested capital is small, the annualised ROI can be very high. The issue is that the proportional prep costs are high and the volume of sales needed to make the model profitable requires a lot of operational capacity.
Mid-range SUVs between £8,000 and £18,000 are usually the segment with the best balance between absolute margin and stock turn speed. An SUV that sells in 35 days with a net margin of £1,600 on an £11,000 capital investment generates an annualised ROI of around 150%, which is hard to beat with other vehicle profiles without taking on more risk.
Read which car brands turn over the fastest in a dealership.
Premium vehicles over £20,000 have high gross margins but slow turn. If the premium SUV takes 90 days and the mid-range one takes 30, the difference in ROI may justify having fewer expensive cars and more mid-range cars with the same amount of capital.
The trap of high margin with low ROI
The most common case of low ROI with an apparently good margin is a car that has spent too much time in stock. A vehicle bought at £16,000 with a gross margin of £2,800 that has gone 120 days unsold has an annualised ROI of approximately 53%. That same car, sold in 40 days, would have an annualised ROI of 160%.
The trap is that the dealership owner sees the £2,800 margin as a good result and doesn't calculate the opportunity cost of having £16,000 tied up for 120 days. If they had dropped the price by £500 on day 45, they would have sold quicker with a margin of £2,300 and a much higher ROI. They would have made less on that deal, but the released capital could have generated another deal with a positive margin.
The rule of thumb is: an early price reduction is almost always better than a long wait. The margin recovered by selling fast outweighs what is lost waiting for a buyer who will pay the original price.
Read also how to reduce days in stock with dynamic pricing.
How to use ROI to decide what to buy
Once you have the historical ROI by vehicle type in your own dealership, you can use it as a buying decision criterion.
The process is: before buying a car, estimate the expected net margin, the capital you are going to invest, and the days you expect it to take to sell based on the history of that vehicle type in your dealership. Calculate the expected annualised ROI. If it is lower than your average business ROI, this deal will hold back capital profitability even if the gross margin looks attractive.
Over time, this analysis allows you to identify which types of vehicles generate the most ROI in your specific market and focus your sourcing on those profiles. The result is not the same in all dealerships: it depends on the area, the sales channels, and the typical buyer profile.
See where the most efficient dealerships buy cars.
Dealcar and stock ROI calculations per vehicle
Calculating the ROI of each deal manually requires keeping a precise record of the entry cost, additional costs, and days in stock of each vehicle. Without a system, this job is tedious and most dealerships stop doing it.
From Dealcar, you can record all the costs associated with each vehicle from the moment of purchase and see the real net margin of each deal upon closing. The dashboard allows you to see the performance by vehicle type and by period, which facilitates ROI analysis without manual reporting. If you want to see how it works, request a demo at dealcar.io.
Frequently Asked Questions
What is a reasonable annualised ROI for a dealership?
It depends on the segment and business model, but as a guide: an annualised ROI below 50% indicates that the stock capital is not being very efficient. Between 80% and 150% is a reasonable range for a dealership with normal rotation. Above 150%, the business is using capital very efficiently, usually because it has good rotation and a good sourcing price.
Does stock ROI include fixed business costs?
Not in the basic calculation per vehicle. The stock ROI described in this article measures the efficiency of the capital invested in the inventory with the direct costs of each operation. The fixed costs of the business (rent, staff, tools) are included in the overall business profitability analysis, not in the ROI per vehicle.
Does it make sense to calculate ROI in a small business?
Yes, especially in small businesses where each deal weighs more on the total result. A dealer selling 8 cars a month has much more room for ROI improvement than one selling 80, because each buying decision impacts the month's result proportionally more.
How does stocking finance affect ROI?
Stocking finance reduces the equity capital invested in each vehicle (since a portion is provided by the finance company), which in principle improves ROI on equity. However, it adds a direct cost for interest that must be included in the net margin calculation. If the cost of financing is less than the benefit of releasing equity capital for more deals, stocking finance improves overall ROI. This is why stocking finance is not just a liquidity tool: properly used, it is a tool for improving ROI.
