The reports only show what gets entered. When job costs don’t match reality, it’s almost always because costs are missing, miscoded, or entered too late to be useful.

The biggest problem is expenses not coded to jobs at the time of purchase. You buy materials at Home Depot for the Smith remodel, but it gets entered as general “materials” with no job assignment. Do that a few times a week across multiple jobs and your reports become meaningless. The same thing happens with crew time. If labor hours aren’t tracked by project daily, you’re guessing at labor costs when the job closes out.

Materials from your yard are another common gap. You pull lumber or supplies from inventory for a job, but nobody records it. That cost sits in your overall materials expense rather than against the specific project where it belongs. The job looks more profitable than it actually was.

Subcontractor costs often get recorded when you pay the invoice rather than when the work happens. If a sub finishes work in March but you don’t pay until April, your March job cost report is understated and April is overstated. Timing matters for seeing true project performance.

Indirect costs rarely make it into job reports at all. Truck expenses, fuel, equipment wear, insurance, and your own time managing the project. These are real costs that eat into margins but most contractors don’t allocate them to jobs. Your reports show material and labor but miss the overhead that makes or breaks profitability.

Change orders create discrepancies too. Work scope changes but the original budget doesn’t get updated. You end up comparing actual costs against a budget that no longer reflects what you agreed to build.

Sometimes the problem starts with how your accounting was set up. A bookkeeper for small business who doesn’t understand construction will create a generic chart of accounts that can’t track costs the way you need. Job costing requires specific configuration: classes or jobs enabled, cost categories that match how you actually buy and build, and reports structured to show margins by project and phase.

The fix isn’t complicated but it requires discipline. Code every expense to a job when it happens. Track labor hours daily by project. Record materials pulled from inventory. Reconcile weekly so you catch errors while you still remember what that charge was for. Allocate a portion of overhead to each job so margins reflect reality.

If you’re not getting useful numbers from your current setup, job costing for contractors done right will align your chart of accounts to field reality and build tracking habits that produce reports you can actually trust.