Accountant for auto repair garages

An accountant for auto repair garages needs to understand workshop economics: estimates, repair orders, parts, labor time, VAT, inventory, warranty work, equipment, payroll and cash collection. A garage can be busy and still lose margin if parts are under-billed, diagnostic time is not charged, or stock is not controlled.

We support independent garages, mechanics, body shops, tire centers and multi-brand repair workshops in France with bookkeeping, VAT returns, payroll, annual accounts and monthly margin reporting.

The most important financial discipline in a garage is separating parts revenue from labor revenue. They have completely different cost and margin profiles.

Parts margin: revenue from selling parts, tires, oils, batteries and consumables minus purchase cost. A well-run garage targets 30–40% gross margin on parts. Erosion happens when parts are sold below target, when free parts are used on flat-rate jobs, or when returns and warranty replacements are not recovered from suppliers.

Labor margin: revenue from billable hours minus the loaded hourly cost of the mechanic. This depends on the sold hourly rate, the number of productive hours per technician and how much non-productive time (training, internal work, waiting) absorbs payroll.

Good accounting must connect the workshop management software (repair orders, invoices) with the bookkeeping, bank flows and inventory to keep both margins visible.

Diagnostic work is one of the most commonly under-billed services in a garage. A complex fault diagnosis can take one to two hours of skilled technician time and require specialized equipment. When that time is absorbed into the repair estimate or given away as a free check, the garage is subsidizing the repair without recognizing it.

Charging explicitly for diagnostic time — as a separate, clearly priced line item — improves margin and sends the right message to clients about the value of the work.

VAT in a garage is more complex than in most trades because the same business may handle standard repair services (20% VAT on labor and parts), used vehicle sales (specific margin VAT scheme taxing only the dealer margin), warranty reimbursements from manufacturers or insurers, and body repair with insurance billing.

VAT errors in a garage typically come from mixing these categories in the invoicing system. The risk is double: a tax risk and a margin-reading error. We set up the accounting to correctly separate and reconcile each VAT flow.

French garages, repair shops, body shops and related businesses typically fall under the Convention Collective Nationale des Services de l'Automobile (IDCC 1090). This agreement covers mechanics, bodywork painters, estimators, reception staff, parts managers, workshop supervisors and administrative employees.

Key payroll dimensions: classification grid with specific minimum wages per grade, apprenticeship and alternance framework, overtime and on-call premia, and workshop foreman pay structures.

Beyond compliance, we track the productive hours of each technician and compare them to billed hours and payroll cost. A mechanic who spends 30% of their time on non-billable work is a drag on margin that shows up monthly, not at year-end.

Parts stock is one of the main cash traps in a garage. Tires, batteries, filters, oils and specific parts ordered speculatively can sit on the shelf for months, tying up cash and eventually becoming obsolete. We categorize stock into active rotation, slow-moving and dormant and flag the dormant stock for clearance or return.

Opening or buying a garage requires a careful pre-investment analysis. We review: the commercial lease and its rent-to-revenue ratio; the condition and value of equipment (hoists, diagnostic tools, compressors, paint booth); starting stock level and cost; staff headcount and loaded payroll cost; existing customer base and revenue continuity after a transfer; and the break-even point at realistic volume.

Not separating parts and labor: a combined margin hides which activity is profitable. Not billing diagnostic time: absorbing diagnosis into the repair estimate destroys labor margin. Ignoring warranty recovery: parts replaced under warranty that are not recovered from the supplier represent a direct margin loss. Letting stock sleep: a well-stocked garage feels professional but ties up cash — stock rotation is a financial KPI. Managing by feel: the daily schedule is not the same as a margin report; monthly reporting disciplines the business.