Construction is one of the hardest industries to keep books for—job costing, retainage, progress billing, and change orders all make it complex. Get it wrong and you can be busy all year and still not know which jobs made money. Here are the mistakes we see most often.
What are the most common construction bookkeeping mistakes?
- Skipping job costing. Without tracking costs by project, you cannot tell profitable jobs from money-losers.
- Ignoring work-in-progress (WIP). Not tracking WIP distorts your profit and can spook lenders and bonding companies.
- Mishandling retainage. Recording retainage as income before it is collected inflates your numbers.
- Not separating direct and indirect costs. Overhead gets buried and job margins look better than they are.
- Falling behind on the books. Month-end never gets done, so decisions are made on stale numbers.
- Mixing personal and business spending. It muddies your margins and creates tax headaches.
- DIY certified payroll. A single WH-347 error can hold up payment on public jobs.
Why does job costing matter so much?
Job costing is how you learn which work actually makes money. It assigns labor, materials, equipment, and subcontractor costs to each project, so you can compare estimated versus actual and price future bids accurately. Without it, you are flying blind.
How do you fix construction bookkeeping?
Set up your books around jobs from the start, track WIP monthly, handle retainage correctly, and reconcile every month. Most contractors find it is faster and cheaper to hand this to a team that knows construction than to fight it in-house.
We handle construction and contractor bookkeeping—job costing, WIP, retainage, and certified payroll—so you always know your real numbers. See our bookkeeping & accounting services.