A shop supplies fee is a small charge — usually a percentage of labor with a dollar cap — that recovers the consumables you burn on every job but never itemize: solder, pipe dope, wire nuts, tape, nitrogen, blades, rags, disposal. Most trades shops that charge one land between 5% and 10% of the labor line with a cap around $30–$50. It is legitimate and defensible, but only if you size it from your actual spend and disclose it on the estimate rather than surprising the customer on the invoice.
Below is how to measure what consumables actually cost you, the three ways to recover that cost, and how to get the answer into your price book so it applies itself.
What a shop supplies fee actually covers
Every job consumes material that is too small, too shared, or too annoying to put on a line item. Nobody bills a customer for eleven inches of Teflon tape. But you bought it, and across 1,400 calls a year it is real money.
Typical consumables by trade:
- HVAC: nitrogen, brazing rod, flux, refrigerant recovery consumables, filter driers on small jobs, foil tape, mastic, sheet metal screws, zip ties, condensate tablets
- Plumbing: solder, flux, pipe dope, Teflon tape, emery cloth, press rings wear, sawzall blades, thread sealant, rags, plumber's putty
- Electrical: wire nuts, staples, anti-oxidant, electrical tape, fish tape wear, drill bits, screws, wire lube, labels
- All trades: shoe covers, drop cloths, gloves, PPE, batteries, shop towels, cleanup supplies, hazardous waste and refrigerant disposal
What a shop supplies fee should not cover: tools, truck payments, fuel, insurance, or anything else that belongs in overhead. Those are recovered through your labor rate. If you are not sure where the line sits, our guide to calculating overhead for contractors walks through what belongs in the overhead bucket and what does not. Double-recovering the same cost in two places is how you end up priced out of jobs you should have won.
How much are consumables actually costing you?
Stop guessing. Pull twelve months of supply-house and big-box receipts, strip out anything that went on a job as a billed line item, and you are left with your true consumables spend. Then divide.
Two denominators work, and they answer different questions:
| Method | Formula | Best when |
|---|---|---|
| Per billable hour | Annual consumables spend ÷ annual billable hours | Long jobs and short jobs burn supplies at different rates |
| Per job | Annual consumables spend ÷ jobs completed | Most calls are similar in length (service-heavy shops) |
A worked example. A four-truck plumbing shop pulls its receipts and finds $18,400 in unbilled consumables last year. The techs booked 5,900 billable hours across 1,320 jobs.
| Input | Value |
|---|---|
| Annual consumables spend | $18,400 |
| Billable hours | 5,900 |
| Cost per billable hour | $3.12 |
| Jobs completed | 1,320 |
| Cost per job | $13.94 |
At a $165/hour billed labor rate, $3.12 per hour is about 1.9% of labor. That is the shop's floor — the number that makes it break even on consumables. A 5% fee on that same labor line collects $8.25 an hour, which is roughly two and a half times cost. That is not price gouging; it is a normal materials margin, and it is the same reasoning behind charging more markup on cheap parts than expensive ones (see material markup by cost band).
Run this calculation once a year. If you have never done it, you are almost certainly under-recovering — this is a cost that only ever moves in one direction.
The stakes are bigger than the line item looks. Contractor magazine puts it plainly: a contractor doing $2 million a year with a combined 5% cost-tracking error is leaving roughly $100,000 on the table. Consumables are one of the leaks that make up that 5%, precisely because each individual instance is too small to notice.
Three ways to recover consumables
There is no single right answer. There is a right answer for your shop.
| Method | How it works | Pros | Cons |
|---|---|---|---|
| Percentage of labor, capped | 5–10% of the labor line, capped at $30–$50 | Scales with job size; easy to explain; visible on the invoice | Customers can question it; some jurisdictions restrict generic fees |
| Flat per-job charge | One fixed amount per call, e.g. $18 | Simple, predictable, easy to quote up front | Over-charges tiny jobs, under-recovers on long ones |
| Baked into labor rate | Add cost-per-hour into the burdened labor rate | No separate line to defend; nothing to disclose | Invisible — easy to forget to update as costs rise |
Flat-rate shops often prefer the third option, because the whole promise of flat-rate pricing is one number with no add-ons — the same tension covered in flat rate vs. time and materials pricing. Time-and-materials shops usually prefer the first, since the customer is already seeing an itemized bill.
Whichever you choose, pick one. Charging a supplies fee and burying consumables in the labor rate means you are billing the same cost twice, and eventually a sharp customer will find it.
What to charge, and where the limits are
The 5–10%-of-labor-with-a-cap convention comes out of vehicle repair, where shop supply fees have been standard for decades; industry guidance there settles on 5–10% of labor with a dollar cap. The trades borrowed the structure, and it works, but the legal precedent sits in a different industry — so do not assume auto-repair rules apply to you, and do not assume they don't.
Two things are true almost everywhere:
- Disclosure beats justification. A fee shown on the estimate before work starts is rarely disputed. The same fee appearing for the first time on a final invoice is the single most common trigger for a chargeback or a complaint.
- Price changes need to be in writing. California, for instance, requires a written contract on home improvement work over $500, and any change to the contract price must be a written, signed change order. Several states have equivalent home improvement statutes. If a supplies fee is not on the original document, adding it later is a change order — handle it like one, using the process in how to price change orders.
Some states and some commercial contracts restrict or cap generic "shop supplies" and "miscellaneous" charges outright, and California's rules for automotive repair dealers are notably strict about itemization and prior authorization. Check your own state's contractor licensing board before you roll a fee out fleet-wide, and read your commercial and property-management agreements — many of them prohibit non-itemized fees.
Putting it in your price book
A supplies fee that lives in a tech's head does not get charged. Make it structural:
- Create it as a real line item in your catalog — "Shop supplies" with a defined percentage or flat amount — so it appears automatically on every quote instead of depending on someone remembering.
- Write the cap into the item so a $4,000 install does not carry a $280 supplies charge that torpedoes the sale.
- Exclude it from equipment-heavy jobs where the labor line is small relative to the price, or the percentage math produces something absurd.
- Recalculate annually alongside your labor burden and overhead review. Consumables inflate quietly.
- Confirm the margin math before you commit to a number — a percentage of labor is markup on a cost, not margin on a price, and the two are not the same thing. Our free margin and markup calculator converts between them, and markup vs. margin for contractors explains why the difference matters.
If your catalog lives in a field-service tool that stores one price per item and no rules, this kind of change becomes a manual pass over hundreds of records. A dedicated price book layer like Pricebookr lets you define the rule once, apply it in bulk, and roll it back if the numbers were wrong.
Finally: measure whether it worked. Compare estimated versus actual consumable cost on a sample of jobs next quarter using the approach in job costing for contractors. If you are still under water, your percentage is too low — not your idea.
FAQ
Is a shop supplies fee legal for contractors?
Generally yes, provided it is disclosed before the work is authorized and reflects a real cost. The risk is not the fee itself but non-disclosure. Several states have home improvement statutes requiring written contracts and written change orders for any price change, and some commercial agreements prohibit non-itemized charges. Check your state contractor board and your customer contracts before rolling one out.
What percentage should I charge for shop supplies?
Five to ten percent of the labor line, capped at roughly $30–$50, is the conventional range. Calculate your own floor first: annual unbilled consumables spend divided by annual billable hours, expressed as a percentage of your billed labor rate. If your floor is 2% and you charge 5%, you are recovering cost plus a normal materials margin.
Should the fee be a percentage or a flat amount?
Use a percentage if job lengths vary widely, because consumption tracks time. Use a flat per-job amount if most of your calls are similar in size — it is easier to quote and easier for customers to accept. Either way, cap the percentage version so large installs do not carry an absurd charge.
Can I just build consumables into my hourly rate instead?
Yes, and many flat-rate shops do exactly that, because it avoids a line item customers can argue with. The downside is that an invisible cost is an easy cost to forget to update. If you go this route, put a recurring annual reminder on the calculation. What you must not do is build it into the rate and charge a separate fee — that bills the same cost twice.
How do I explain the fee to a customer who pushes back?
Name what it covers in concrete terms: "That covers the solder, tape, sealant, blades and disposal we used today — itemizing eleven cents of Teflon tape costs more to process than the tape." Then point out it was on the estimate they approved. The conversation goes badly only when it is the first time they are hearing about it.
Does a shop supplies fee replace a trip charge or diagnostic fee?
No. They cover different costs. A diagnostic fee pays for the technician's time and expertise in identifying the problem, and a trip charge covers travel. A supplies fee covers physical consumables used on site. Many shops charge all three, disclosed separately.