How it is computed
Take parts sales for the period. Subtract parts cost. That is parts gross in dollars. Divide by parts sales for the percent. Run it by channel: repair-order parts, counter retail, and wholesale carry different margins by design, and a blended percent hides which one moved.
Why it matters
Every labor hour sold on the drive pulls parts with it, so parts gross follows hours per repair order the way a trailer follows a truck. A shop that grows its hours and does not see parts gross rise has a pricing or a sourcing problem.
Wholesale parts are volume at thin margin on purpose. Counting them with the drive flatters the sales line and hides the retail margin.
How operators read it
- Read it by channel first. Repair-order parts, counter, and wholesale each have their own margin and their own reason to move.
- Read it against labor on the same tickets. The ratio of parts to labor on customer-pay work is a stable signature for a shop; when it drifts, something in the pricing matrix or the sourcing changed.
- Watch obsolescence. Parts gross can look fine while the shelf fills with parts that will never sell; the write-down arrives later and all at once.
Questions people ask
Is parts gross part of fixed operations?
Yes. Service, parts, and body shop are the fixed side of the building, and parts gross is one of the three pieces of the absorption calculation.
Why does wholesale parts gross run thin?
Because the customer is another shop buying in volume at a matrix price. It earns its keep on turn and on keeping the parts department busy, not on margin per line.
How A.D.A.M. reads it
A.D.A.M. reads parts gross with labor on the same repair orders, treating each ticket as labor sale plus parts gross, so the two halves of the service drive are never judged apart. He reads it beside the numbers it trades against, names what the gap is worth, and leaves the decision where it belongs. What an AI advisor should do, and refuse to do.