Index
What information is needed per vehicle for accounting
The purchase document: the starting point of everything
Expenses associated with the vehicle: what is included and how it is recorded
How to calculate the full real cost of each vehicle
Why Excel stops working after a certain volume
The sales invoice: what it must include according to the applied scheme
How to organise the monthly dispatch to the agency
The most time-consuming errors at the end of the quarter
Dealcar and the accounting documentation integrated into the file
Frequently Asked Questions
What information is needed per vehicle for accounting
The accounting of a second-hand dealership works vehicle by vehicle. Unlike a business that sells a standard product always at the same price, in the dealership each operation has a different entry cost, variable expenses and a different sale price. This makes it necessary to keep an individualised record of each car.
For each vehicle, the agency needs four blocks of information: the purchase cost with its receipt, the direct expenses associated with the vehicle (transport, repair, transfer agency fees), the sale price and the tax scheme applied (REBU or general VAT). With these four pieces of data, the agency can calculate the margin, determine the corresponding VAT and classify the operation correctly in the quarterly return.
If any of those blocks arrive incomplete or mixed with information from other cars, the agency's work multiplies. The cost is not just financial: it is also in response time and risk of error.
The purchase document: the starting point of everything
The purchase document is the first paper that must be held for each vehicle that enters stock. It can be an invoice (if bought from a company or sole trader), a sales contract (if bought from an individual) or the delivery note from an auction or professional platform.
That document must include the name and NIF or DNI of the seller, the description of the vehicle (registration number, VIN, make and model), the date of the transaction and the purchase price. For REBU transactions with an individual, that document is also the proof that certifies that the vehicle was bought from someone who could not pass on VAT, which justifies the application of the special scheme on resale.
Read also what documentation the Tax Agency requires to justify a REBU transaction.
If the purchase document reaches the agency without the seller's NIF, without the vehicle registration number or without a date, it must be requested again from the seller before the end of the quarter. This delay is the most frequent and the most avoidable if the documentation is verified at the time of purchase, not weeks later.
Expenses associated with the vehicle: what is included and how it is recorded
The expenses directly attributable to each vehicle are those that form part of the actual cost of the transaction and which, depending on the tax scheme, can reduce the taxable margin or be recorded as a deductible business expense.
Check which expenses reduce the REBU margin and which do not.
The most common expenses are transport of the vehicle from source, mechanical or bodywork repairs carried out before sale, the cost of the agency for the transfer to the dealership's name or to the final customer, inspection fees if the vehicle had to pass an MOT, and in some cases cosmetic preparation costs if they are invoiced separately.
Each of those expenses must be documented with an invoice in the name of the dealership that includes a reference to the specific vehicle: the registration number or the VIN. Without that reference, the agency cannot associate the expense with the correct vehicle and may record it as a general business expense instead of an operational cost, which distorts the calculation of the actual margin per vehicle.
General business expenses (rent of the premises, listing portals, management tools, payroll) are not vehicle expenses: they are structural expenses that are accounted for at the business level, not per transaction.
Read also the accounting obligations and deductible expenses of a dealership.
How to calculate the full real cost of each vehicle
The real cost of a vehicle is not just the price paid when buying it. It is the sum of all the outlays that the dealership has made from the moment the car entered stock until it was sold. This figure is what determines the real net margin of the transaction, and without it any profitability analysis is an estimate.
The components of the real cost are five. The purchase price is the amount paid to the seller, documented with the contract or purchase invoice. Transport is the cost of bringing the vehicle from source to the dealership, documented with the carrier's invoice. Repairs are the mechanical or bodywork tasks necessary to put the vehicle in saleable condition, documented with the garage's invoice referencing the vehicle. The agency is the cost of the transfer process to the dealership's name or to the final customer, documented with the agency's invoice. And financial costs are the interest on the stock finance line during the days the vehicle has been in inventory, if the car is financed.
Check also the hidden costs of a dealership that eat away at the margin.
Example with numbers: a dealership buys a Volkswagen Golf from an individual for 12,800 euros. They pay 280 euros for transport, 650 euros to a garage to fix the clutch and change the brake pads, 120 euros for agency fees for the transfer, and it has been in stock for 35 days with a financing line at 7% per annum. The financing cost for those 35 days is 85.70 euros (12,800 × 0.07 / 365 × 35). The total real cost of the vehicle is 13,935.70 euros. If sold for 16,200 euros, the net margin is 2,264.30 euros, not 3,400 euros as it would seem if only looking at the difference between purchase price and sales price.
Recording these five components for each vehicle at the time they occur, not at the end of the month, is what makes the margin calculation reliable.
Why Excel stops working after a certain volume
Excel is the tool most dealerships start with to control the margin per vehicle. For 5 or 6 cars a month, it works. From 15 or 20 onwards, it begins to generate more problems than solutions.
The first problem is manual data entry. Every purchase, every expense and every sale must be entered manually into the sheet. A typographical error in an amount or in a registration plate has no automatic detection mechanism and can go undetected for weeks.
The second is the lack of connection between documents. In Excel, the purchase invoice, expense invoices and sales invoice are data in different cells that the user has to connect mentally. If someone updates the purchase price without updating the margin calculation, the margin remains outdated without anyone knowing.
The third is that Excel does not generate the REBU register book in the format required by the Tax Agency. The data is in the sheet but the register book has to be built separately, copying and reorganising the information manually every quarter.
The fourth and most important since July 2025 is that Excel is not compatible with Verifactu. Invoices issued from Word or Excel templates do not generate the verifiable billing record required by the AEAT system. If these tools are still used for invoicing, it is necessary to migrate to certified software.
Read also what Verifactu requires and why Excel is no longer valid for invoicing.
The alternative to Excel for controlling the margin per vehicle is not a general accounting programme like Holded or Sage, which do not have files per vehicle either. It is a specific DMS for dealerships that records all cost components in the file of each car and calculates the margin automatically at the close of each transaction.
The sales invoice: what it must include according to the applied scheme
The sales invoice to the final customer is the last document in the accounting cycle of each vehicle. Its content varies depending on the tax scheme applied.
Under the REBU, the invoice includes the total price without breakdown of VAT, with explicit mention of the special scheme applied. The buyer cannot deduct the VAT from that invoice because it is not broken down. The invoice must have an invoice number, date, details of the issuer (name, CIF, address), details of the recipient and description of the vehicle.
Under the general VAT scheme, the invoice includes the taxable base, the VAT rate (21%) and the VAT amount broken down separately. The corporate buyer can deduct that VAT. The invoice follows the same standard format as any general VAT invoice.
For Verifactu operations, the invoicing software must send a record of each invoice to the Tax Agency at the time of its issue. If the programme is not certified for Verifactu, invoices issued from 1 July 2025 will not comply with the regulations.
Check which REBU invoicing programme must comply with Verifactu.
How to organise the monthly dispatch to the agency
The most efficient method for preparing monthly accounting documentation is to organise the information by vehicle from day one, not at the end of the month.
The process has three steps. When buying the vehicle, file the purchase document with the seller's NIF and the vehicle reference. During the time in stock, keep accumulating the expense invoices associated with that vehicle with its reference. When closing the sale, generate the invoice with the correct scheme and gather the four documents (purchase, expenses, sale, applied scheme) in the vehicle's file.
At the end of the month, sending it to the agency is an export of those ordered files, not a search for loose invoices on WhatsApp, emails and physical folders. The difference in time and errors is significant.
A monthly summary that includes the number of REBU transactions with their total taxable base, the number of transactions under the general scheme with their output VAT and the general expenses for the period helps the agency prepare Form 303 without the need for back-and-forth questions.
Check what data must be recorded in the REBU register book per transaction.
The most time-consuming errors at the end of the quarter
Sending purchase invoices without the seller's NIF. The agency has to ask the dealership for it, which has to get it from the private seller weeks after the operation. If the seller no longer responds, the documentation remains incomplete.
Mixing vehicle expenses with general expenses without reference to the car. A garage invoice without the vehicle registration number may end up recorded as a general expense instead of an operational cost, which overestimates the margin.
Recording the sale without specifying whether it is REBU or general scheme. The agency cannot prepare Form 303 without knowing which scheme applies to each sales invoice.
Not recording deposits and reservations in a differentiated way. A deposit received before signing the contract is not a sale. If registered as such, the VAT is accrued ahead of time and the quarter's Form 303 may be wrong.
Reaching the end of the quarter without having the REBU register book updated. Reconstructing 60 or 90 days of transactions in the final days before closing is an avoidable source of errors.
Read also when to pay and what documents to use in B2B transactions.
Dealcar and the accounting documentation integrated into the file
With Dealcar, each vehicle has its file with the purchase cost, associated expenses, sale price and applied tax scheme. This information is available to the agency at any time, without the need to reconstruct it at the end of the month.
Check how the integrated agency service of Dealcar works.
The REBU register book is updated automatically with each transaction. The sales invoice is generated from the file with the correct scheme already applied.
Visit the management software page for Dealcar dealerships.
At the close of the quarter, exporting data to the format the agency needs takes minutes, not hours. If you want to see how it works:
Frequently Asked Questions
Is it mandatory to have the NIF of the private seller on the purchase document?
Yes. The NIF is one of the mandatory details on the proof of purchase in order to prove the REBU origin to the Tax Agency. Without that detail, the document is not sufficient to justify the application of the special scheme in an audit.
Do repair costs always reduce the REBU margin?
Repairs linked to the vehicle and documented with an invoice referencing the car do reduce the REBU margin. Cosmetic preparation costs (cleaning, polishing) are a less clear case that should be consulted with the tax advisor. General business expenses do not reduce the REBU margin.
When must the sales invoice be issued: upon signing the contract or upon delivery of the vehicle?
VAT is accrued at the time of delivery of the vehicle or payment if collected before delivery, whichever occurs first. The invoice must be issued at that moment. Deposits and reservations prior to delivery are not sales and must not be invoiced as such.
What format does the agency accept for receiving accounting data?
It depends on the agency and the software they use. Most work with Excel, CSV or imports from standard accounting software. A management system that allows exporting data in the format needed by the specific agency eliminates manual transcription work.
Index
What information is needed per vehicle for accounting
The purchase document: the starting point of everything
Expenses associated with the vehicle: what is included and how it is recorded
How to calculate the full real cost of each vehicle
Why Excel stops working after a certain volume
The sales invoice: what it must include according to the applied scheme
How to organise the monthly dispatch to the agency
The most time-consuming errors at the end of the quarter
Dealcar and the accounting documentation integrated into the file
Frequently Asked Questions
What information is needed per vehicle for accounting
The accounting of a second-hand dealership works vehicle by vehicle. Unlike a business that sells a standard product always at the same price, in the dealership each operation has a different entry cost, variable expenses and a different sale price. This makes it necessary to keep an individualised record of each car.
For each vehicle, the agency needs four blocks of information: the purchase cost with its receipt, the direct expenses associated with the vehicle (transport, repair, transfer agency fees), the sale price and the tax scheme applied (REBU or general VAT). With these four pieces of data, the agency can calculate the margin, determine the corresponding VAT and classify the operation correctly in the quarterly return.
If any of those blocks arrive incomplete or mixed with information from other cars, the agency's work multiplies. The cost is not just financial: it is also in response time and risk of error.
The purchase document: the starting point of everything
The purchase document is the first paper that must be held for each vehicle that enters stock. It can be an invoice (if bought from a company or sole trader), a sales contract (if bought from an individual) or the delivery note from an auction or professional platform.
That document must include the name and NIF or DNI of the seller, the description of the vehicle (registration number, VIN, make and model), the date of the transaction and the purchase price. For REBU transactions with an individual, that document is also the proof that certifies that the vehicle was bought from someone who could not pass on VAT, which justifies the application of the special scheme on resale.
Read also what documentation the Tax Agency requires to justify a REBU transaction.
If the purchase document reaches the agency without the seller's NIF, without the vehicle registration number or without a date, it must be requested again from the seller before the end of the quarter. This delay is the most frequent and the most avoidable if the documentation is verified at the time of purchase, not weeks later.
Expenses associated with the vehicle: what is included and how it is recorded
The expenses directly attributable to each vehicle are those that form part of the actual cost of the transaction and which, depending on the tax scheme, can reduce the taxable margin or be recorded as a deductible business expense.
Check which expenses reduce the REBU margin and which do not.
The most common expenses are transport of the vehicle from source, mechanical or bodywork repairs carried out before sale, the cost of the agency for the transfer to the dealership's name or to the final customer, inspection fees if the vehicle had to pass an MOT, and in some cases cosmetic preparation costs if they are invoiced separately.
Each of those expenses must be documented with an invoice in the name of the dealership that includes a reference to the specific vehicle: the registration number or the VIN. Without that reference, the agency cannot associate the expense with the correct vehicle and may record it as a general business expense instead of an operational cost, which distorts the calculation of the actual margin per vehicle.
General business expenses (rent of the premises, listing portals, management tools, payroll) are not vehicle expenses: they are structural expenses that are accounted for at the business level, not per transaction.
Read also the accounting obligations and deductible expenses of a dealership.
How to calculate the full real cost of each vehicle
The real cost of a vehicle is not just the price paid when buying it. It is the sum of all the outlays that the dealership has made from the moment the car entered stock until it was sold. This figure is what determines the real net margin of the transaction, and without it any profitability analysis is an estimate.
The components of the real cost are five. The purchase price is the amount paid to the seller, documented with the contract or purchase invoice. Transport is the cost of bringing the vehicle from source to the dealership, documented with the carrier's invoice. Repairs are the mechanical or bodywork tasks necessary to put the vehicle in saleable condition, documented with the garage's invoice referencing the vehicle. The agency is the cost of the transfer process to the dealership's name or to the final customer, documented with the agency's invoice. And financial costs are the interest on the stock finance line during the days the vehicle has been in inventory, if the car is financed.
Check also the hidden costs of a dealership that eat away at the margin.
Example with numbers: a dealership buys a Volkswagen Golf from an individual for 12,800 euros. They pay 280 euros for transport, 650 euros to a garage to fix the clutch and change the brake pads, 120 euros for agency fees for the transfer, and it has been in stock for 35 days with a financing line at 7% per annum. The financing cost for those 35 days is 85.70 euros (12,800 × 0.07 / 365 × 35). The total real cost of the vehicle is 13,935.70 euros. If sold for 16,200 euros, the net margin is 2,264.30 euros, not 3,400 euros as it would seem if only looking at the difference between purchase price and sales price.
Recording these five components for each vehicle at the time they occur, not at the end of the month, is what makes the margin calculation reliable.
Why Excel stops working after a certain volume
Excel is the tool most dealerships start with to control the margin per vehicle. For 5 or 6 cars a month, it works. From 15 or 20 onwards, it begins to generate more problems than solutions.
The first problem is manual data entry. Every purchase, every expense and every sale must be entered manually into the sheet. A typographical error in an amount or in a registration plate has no automatic detection mechanism and can go undetected for weeks.
The second is the lack of connection between documents. In Excel, the purchase invoice, expense invoices and sales invoice are data in different cells that the user has to connect mentally. If someone updates the purchase price without updating the margin calculation, the margin remains outdated without anyone knowing.
The third is that Excel does not generate the REBU register book in the format required by the Tax Agency. The data is in the sheet but the register book has to be built separately, copying and reorganising the information manually every quarter.
The fourth and most important since July 2025 is that Excel is not compatible with Verifactu. Invoices issued from Word or Excel templates do not generate the verifiable billing record required by the AEAT system. If these tools are still used for invoicing, it is necessary to migrate to certified software.
Read also what Verifactu requires and why Excel is no longer valid for invoicing.
The alternative to Excel for controlling the margin per vehicle is not a general accounting programme like Holded or Sage, which do not have files per vehicle either. It is a specific DMS for dealerships that records all cost components in the file of each car and calculates the margin automatically at the close of each transaction.
The sales invoice: what it must include according to the applied scheme
The sales invoice to the final customer is the last document in the accounting cycle of each vehicle. Its content varies depending on the tax scheme applied.
Under the REBU, the invoice includes the total price without breakdown of VAT, with explicit mention of the special scheme applied. The buyer cannot deduct the VAT from that invoice because it is not broken down. The invoice must have an invoice number, date, details of the issuer (name, CIF, address), details of the recipient and description of the vehicle.
Under the general VAT scheme, the invoice includes the taxable base, the VAT rate (21%) and the VAT amount broken down separately. The corporate buyer can deduct that VAT. The invoice follows the same standard format as any general VAT invoice.
For Verifactu operations, the invoicing software must send a record of each invoice to the Tax Agency at the time of its issue. If the programme is not certified for Verifactu, invoices issued from 1 July 2025 will not comply with the regulations.
Check which REBU invoicing programme must comply with Verifactu.
How to organise the monthly dispatch to the agency
The most efficient method for preparing monthly accounting documentation is to organise the information by vehicle from day one, not at the end of the month.
The process has three steps. When buying the vehicle, file the purchase document with the seller's NIF and the vehicle reference. During the time in stock, keep accumulating the expense invoices associated with that vehicle with its reference. When closing the sale, generate the invoice with the correct scheme and gather the four documents (purchase, expenses, sale, applied scheme) in the vehicle's file.
At the end of the month, sending it to the agency is an export of those ordered files, not a search for loose invoices on WhatsApp, emails and physical folders. The difference in time and errors is significant.
A monthly summary that includes the number of REBU transactions with their total taxable base, the number of transactions under the general scheme with their output VAT and the general expenses for the period helps the agency prepare Form 303 without the need for back-and-forth questions.
Check what data must be recorded in the REBU register book per transaction.
The most time-consuming errors at the end of the quarter
Sending purchase invoices without the seller's NIF. The agency has to ask the dealership for it, which has to get it from the private seller weeks after the operation. If the seller no longer responds, the documentation remains incomplete.
Mixing vehicle expenses with general expenses without reference to the car. A garage invoice without the vehicle registration number may end up recorded as a general expense instead of an operational cost, which overestimates the margin.
Recording the sale without specifying whether it is REBU or general scheme. The agency cannot prepare Form 303 without knowing which scheme applies to each sales invoice.
Not recording deposits and reservations in a differentiated way. A deposit received before signing the contract is not a sale. If registered as such, the VAT is accrued ahead of time and the quarter's Form 303 may be wrong.
Reaching the end of the quarter without having the REBU register book updated. Reconstructing 60 or 90 days of transactions in the final days before closing is an avoidable source of errors.
Read also when to pay and what documents to use in B2B transactions.
Dealcar and the accounting documentation integrated into the file
With Dealcar, each vehicle has its file with the purchase cost, associated expenses, sale price and applied tax scheme. This information is available to the agency at any time, without the need to reconstruct it at the end of the month.
Check how the integrated agency service of Dealcar works.
The REBU register book is updated automatically with each transaction. The sales invoice is generated from the file with the correct scheme already applied.
Visit the management software page for Dealcar dealerships.
At the close of the quarter, exporting data to the format the agency needs takes minutes, not hours. If you want to see how it works:
Frequently Asked Questions
Is it mandatory to have the NIF of the private seller on the purchase document?
Yes. The NIF is one of the mandatory details on the proof of purchase in order to prove the REBU origin to the Tax Agency. Without that detail, the document is not sufficient to justify the application of the special scheme in an audit.
Do repair costs always reduce the REBU margin?
Repairs linked to the vehicle and documented with an invoice referencing the car do reduce the REBU margin. Cosmetic preparation costs (cleaning, polishing) are a less clear case that should be consulted with the tax advisor. General business expenses do not reduce the REBU margin.
When must the sales invoice be issued: upon signing the contract or upon delivery of the vehicle?
VAT is accrued at the time of delivery of the vehicle or payment if collected before delivery, whichever occurs first. The invoice must be issued at that moment. Deposits and reservations prior to delivery are not sales and must not be invoiced as such.
What format does the agency accept for receiving accounting data?
It depends on the agency and the software they use. Most work with Excel, CSV or imports from standard accounting software. A management system that allows exporting data in the format needed by the specific agency eliminates manual transcription work.
