Parts markup for mobile mechanics: how to set it and explain it

If your labor rate is the only place you make money, every parts run is unpaid work.

• Time finding the right part and calling around for stock.
• The trip to pick it up, or waiting on delivery.
• Returns and core charges you handle for the customer.
• Standing behind the part if it fails early: the second visit is usually on you.
• Parts that arrive wrong or damaged and cost you a day.

Some mechanics use a flat percentage on everything. Others use a sliding scale: a higher percentage on cheap parts (where the handling time is the same but the dollar amount is small) and a lower one on expensive parts like a transmission or a module. A sliding scale tends to feel fairer to customers on big jobs.

Whatever you pick, write it down and use it every time. Inconsistent markup is what makes customers suspicious, not markup itself.

Most customers don’t want a line-by-line breakdown of your cost and margin. They want to know the total, what it includes, and that it won’t change without asking them. Give the parts total with a short description of each part, and keep your cost price to yourself.

If a customer asks why the part is cheaper online, the honest answer works: you’re supplying the part, picking it up, and standing behind it if it fails. Some mechanics will install customer-supplied parts with no warranty on the part; decide your policy before someone asks.

Once the customer approves a parts total, that’s the number. If the price changes before you buy (a supplier price change, or the part is backordered and the alternative costs more), send a new approval rather than adjusting the bill afterward.