Auto repair shop bookkeeping: margins by repair order, not by month

Everything rolls up from the repair order

Your shop management system — Tekmetric, Protractor, or Mitchell 1 — already splits every ticket into labour, parts, sublet, and fees. The bookkeeping's job is to carry that split into QuickBooks Online daily instead of flattening it, so the ledger can answer shop questions: what is my effective labour rate, what is my true parts margin, which fees actually get charged.

Daily sales postings then reconcile against card batches and the bank, and supplier invoices arrive through Dext coded to parts, sublet, or shop supplies as they land — not sorted from a pile at year end.

Parts margin and labour margin fail differently

Labour margin is an hours problem: the spread between hours billed at the door rate and hours paid on the clock, eroded by unapplied time, comebacks, and diagnosis given away free. Parts margin is a discipline problem: the matrix actually applied at the counter, jobber returns actually credited, cores actually sent back. Because the failure modes differ, blending the two into one gross-profit line hides both.

We report both margins monthly, with the effective labour rate — billed labour dollars divided by all technician hours paid — as the single most honest number in the shop. Pay plans change what that number means: flat-rate techs make labour cost move with the work while hourly techs make it fixed, so the same slow week costs the two shops very differently, and the books should show which one you are running.

Open ROs are work in progress, not revenue

A vehicle on the hoist at month end has parts hung and hours clocked, but the sale has not happened until the customer picks it up. Those costs sit in WIP, and revenue lands on delivery, which keeps months comparable — otherwise a strong month is often just next month's work invoiced early. Deposits taken for special-order parts are liabilities until the part is fitted, and an RO that lives in WIP too long is its own red flag: a parts backorder, an unapproved estimate, or a car quietly becoming a lawn ornament.

Insurance work turns a repair into a receivable

Collision and insurance jobs split every invoice in two: the deductible collected from the customer at pickup, and the balance owed by the insurer weeks later. The billed amount has to match the approved estimate plus supplements — the additional amounts approved after teardown in Audatex or Mitchell — because unmatched supplements are the most common source of short-pays.

We age receivables by insurer, not in one lump, so slow payers and habitual short-payers are visible as patterns, and disputes get chased while photos and approvals are still fresh. Warranty work billed to OEMs at prescribed warranty rates gets its own revenue line for the same reason: three payer types, three margins, three collection speeds.

Fleet and commercial accounts behave like insurers without the estimating software — negotiated rates, monthly statements, and net-30 terms that quietly stretch to net-60. They get their own aging too, because a fleet that fills your bays while falling behind on payment is a loan you never agreed to make.

Imported parts, HST, and the close

US-sourced parts now arrive carrying duty, brokerage, and exchange on top of the invoice price, and all of it belongs in the landed cost that hits the RO — otherwise import-heavy jobs look more profitable than they are. Tariff cost pass-through and warranty reimbursements from US OEMs are covered in our cross-border tax guide for auto repair shops.

On HST, shop revenue is taxable and the input tax credits on parts, equipment, and rent are significant — captured monthly, they fund the quarterly remittance instead of surprising it. The full monthly close routine is described on our bookkeeping services page.