AUTO REPAIR ESTIMATE CALCULATOR

What this estimator actually computes

Four numbers turn a job list into a price. Labor is book hours times your door rate. Parts are supplier cost grossed up to a target margin — not cost plus a flat percentage, which is the mistake that leaves money on cheap parts and prices you out of expensive ones. Shop supplies are a percentage of labor with a hard cap. Tax lands on the subtotal.

The parts line uses sell = cost ÷ (1 − GP%), which is the formula a matrix implements at every tier. A 55% target on a $186 rotor set sells at $413, not $288 — the difference between marking up and marking to margin.

How to use it on a real repair order

1. 01Set the door rate first. If you have not set one deliberately, run the labor rate calculator before you quote anything.
2. 02Enter book hours, not clock hours. A labor time guide is what makes the number defensible when a customer asks why the job takes 1.8 hours.
3. 03Put your supplier cost in the parts column, not your sell price. The sheet does the margin. Once you write a dozen of these a day, applying that markup at estimate time is the job shop management software takes over.
4. 04Print. The printed sheet drops the coloured copies and the buttons and leaves an estimate with a signature line.

The worked example in the sheet

The seed data is a front brake job on a mid-size sedan: pads and rotors at 1.8 hours, a fluid flush at 0.8, and a four-wheel inspection at 0.3. At a $140 door rate that is 2.9 hours of labor, $198 of parts cost grossed to 55%, and a capped supplies fee. The total lands inside the published per-axle band, which is the check that tells you the estimate is sane before the customer does.

An estimate is not a quote

Most states treat a written estimate and a fixed-price quote differently, and several require the customer’s documented authorisation (written, oral or electronic, depending on the state) before work exceeds the estimate by a set amount or percentage. The sheet leaves the authorisation line blank on purpose. Have your own counsel check the form against your state’s consumer-repair rules before it goes in front of a customer — see the terms. The state-by-state rules, with citations, are in the guide to auto repair written estimate laws.