Guide · Trades & Contractors

Inventory management for contractors & trades

Last updated July 2026 · 6 min read

For trades, inventory isn't a stockroom problem — it's a profitability problem. Materials flow from a supplier, into a van, onto a job, and (hopefully) onto an invoice. Money leaks at every step you can't see, and most contractors only find out at year-end that certain jobs quietly lost money.

The two biggest material leaks

• Unbilled materials — the fittings, fasteners, and extras used on a job that never made it onto the invoice. On thin margins, a few forgotten items per job adds up to real money.
• Van & site shrinkage — stock that walks off, gets miscounted, or is "borrowed" between jobs and never replaced.

Both are invisible without a system that connects materials to jobs and keeps a running count.

What to track

• Material stock — what's in the warehouse and each van, by item and quantity.
• Job draws — what materials were pulled for each job, so cost lands on the right job.
• Job costing — quoted price vs. actual material (and labor) cost per job.
• Material takeoffs / BOM — the list of materials a job needs, so you order and stage the right amounts.
• Reorder points — for common consumables so you're never stuck mid-job.

Job costing: which jobs actually pay

Job costing assigns material cost to a specific job so you can compare what you quoted against what it actually cost. Do it across a few months and patterns emerge: certain job types, customers, or crews consistently come in over cost. That's the difference between "we're busy" and "we're profitable" — and you can only see it if materials are tied to jobs.

Spreadsheets vs. software for trades

A spreadsheet can hold a materials list, but it won't follow materials from van to job to invoice, won't warn you before you run out of a common consumable, and won't tell you which jobs lost money. Once you're running multiple jobs and vans, software that ties materials to jobs pays for itself in recovered unbilled materials alone.

How AIM helps contractors

AIM's trades setup tracks material stock across warehouse and vans, lets you draw materials against jobs, and reports job profitability — quoted vs. actual — so you see which work pays. Build material takeoffs/BOMs for upcoming jobs, set reorder points on consumables, and stop losing margin to unbilled materials and van shrinkage. Free to start, $14/month for a single operation.