Get this right and you know which jobs make money, which crews run over, and whether that next bid is priced correctly. Get it wrong and your books show profitability your bank account doesn't reflect — which is how contractors end up cash-poor in the middle of a busy year.
This guide covers what construction businesses need to track and why each category matters.
1. Job costing
Job costing is the foundation of construction bookkeeping. Every cost — labor, materials, equipment, subcontractor payments, overhead allocation — has to be assigned to a specific job.
Without job costing, your books tell you whether the business is profitable. With job costing, they tell you whether each job is profitable. That's the difference between guessing and pricing your next bid intelligently.
What to track per job:
- Direct labor hours and burdened labor cost
- Materials purchased for the job
- Equipment time (owned or rented)
- Subcontractor payments
- Permits, fees, and other direct costs
- Allocated overhead (if you track it)
The job cost system needs to live inside your bookkeeping, not in a separate spreadsheet that doesn't reconcile. QuickBooks handles job costing natively. Construction-specific platforms (Buildertrend, Procore, Sage 100 Contractor) handle it more robustly once you're past a certain volume.
2. Change orders
Change orders are where a lot of construction profit either gets made or quietly disappears. The client wants something added, scope shifts, materials change — and if those changes aren't properly documented and billed, the contractor eats the cost.
What your books need to handle:
- Original contract value vs. revised contract value (with change orders applied)
- A clear paper trail showing client approval of each change order
- The cost impact of each change order, tracked against the same job
The pattern we see most often: change orders happen verbally, work gets done, billing lags, and the contractor either has to fight to get paid or writes off the difference. Tighter bookkeeping doesn't fix the human conversation, but it makes the financial side of every change order trackable.
3. Retainage
Retainage is the percentage of each progress payment the client holds back (commonly 5–10%) until the job is satisfactorily completed. It's a normal part of commercial construction, but it has to be tracked separately in your books.
What to track:
- Retainage receivable on each job (amounts being held by clients)
- Retainage payable on each job (amounts you're holding from subcontractors)
- When retainage is expected to be released
The reason this matters: retainage looks like revenue you've earned, but it's not cash you've received. Treating it as the same number creates a cash flow mirage. A profitable-looking year with significant retainage outstanding can leave you short of payroll if the timing doesn't line up.
4. Subcontractors and 1099s
Most construction businesses run on a combination of W-2 employees and 1099 subcontractors. The bookkeeping requirements differ:
- Employees: payroll, withholding, employer-side payroll taxes, workers' comp, W-2s at year-end
- Subcontractors: collect W-9 before paying, track payments to each, issue 1099-NECs at year-end if thresholds are met
For 2026 payments, the 1099-NEC threshold rose from $600 to $2,000 under the One Big Beautiful Bill Act. (Full 1099 walkthrough →)
Two specific construction-related notes:
- Worker classification matters. Construction has historically been a focus area for IRS misclassification audits. If a "subcontractor" works only for you, on your schedule, with your tools, they're probably an employee — and reclassification can be expensive.
- Verify subcontractor insurance and licensing. Bookkeeping doesn't fix this, but it should track whether each sub has current insurance certificates on file. Subs without insurance can become your liability problem.
5. Equipment and depreciation
Construction equipment is a major asset class, and how it's tracked affects both your books and your taxes:
- Purchase price and date placed in service
- Depreciation schedule (straight-line, accelerated, Section 179, bonus depreciation)
- Maintenance and repair costs
- Allocation of equipment time to jobs (if billed)
For owned equipment, the depreciation schedule matters for tax purposes. For rented equipment, costs should be charged directly to the job they were used on.
A common mistake: treating all equipment as a generic overhead expense instead of allocating it to jobs. That hides equipment cost from job profitability analysis.
6. Materials and inventory
Construction businesses often hold inventory — materials purchased in bulk for ongoing or upcoming jobs. Whether you track it depends on volume:
- Smaller residential contractors can typically expense materials as purchased (charged directly to jobs).
- Larger contractors and supply-heavy businesses should track inventory more formally, with materials counted and valued at period-end.
The decision affects both your books and your tax position. Once inventory is meaningful — say, $50k+ on hand at any point — the IRS expects you to track it properly. Talk to your CPA about what your business needs.
7. WIP (work-in-progress) reporting
WIP reporting is one of the most useful tools in construction accounting and one of the most under-used by small contractors. It shows, for each open job, the difference between what you've billed and what you've actually earned (based on costs incurred vs. estimated total costs).
The two scenarios WIP catches:
- Overbilling — you've billed more than you've earned, meaning future labor and materials still need to be delivered against money already collected
- Underbilling — you've spent more than you've billed, meaning you have earned revenue not yet on the books
Both are normal mid-project. The problem is when one or both are large and surprising — that's where contractors get blindsided.
WIP reporting requires good job costing and consistent estimates. It's not realistic for one-person operations doing small jobs. It's nearly mandatory for any business doing commercial work or jobs that span multiple months.
Common mistakes
The patterns we see most often in construction books:
- No job costing. Profitability is invisible at the job level.
- Treating retainage as cash. Creates a cash flow surprise when bills come due.
- Mixing personal and business finances — especially common in owner-operated trades.
- Forgetting to bill change orders promptly or not having documented approval.
- Late W-9 collection from subs. January becomes a scramble.
- Misclassifying subcontractors who should be employees. Audit risk.
- No WIP visibility. Profitable-looking jobs end up being losses at close.
Most of these compound — and most are fixable with better bookkeeping discipline, not specialized software.
Frequently asked questions
Not necessarily. QuickBooks handles job costing, change orders, and most of what small contractors need. Construction-specific platforms (Sage 100 Contractor, Foundation, Buildertrend with accounting integration) become worth it when you're managing many jobs, multiple crews, or commercial work with complex billing.
Monthly at minimum. Weekly job cost reports are common in commercial construction — labor and materials move fast enough that monthly visibility may be too slow to catch problems in time.
Anything with a useful life of more than a year and meaningful cost is an asset — depreciated over time, not expensed immediately. Small tools and consumables under the IRS de minimis safe harbor amount can be expensed directly. Talk to your CPA about your specific threshold.
Cash accounting recognizes revenue and expenses when money actually moves. Accrual accounting recognizes them when earned or incurred. For construction, accrual is usually more accurate because of the lag between work done and payment received. The IRS has specific rules about which method you can use based on revenue size and business structure — this is a CPA conversation.
Where to start
If your construction books don't show profit by job, retainage isn't tracked separately, or you can't tell at any moment which open jobs are running over budget, those are the gaps to close first. The software handles it once it's set up right.
SoFlo360 works with construction businesses on monthly bookkeeping, catch-up, and cleanup of files that have outgrown their original setup. Spanish-friendly support is available for owners who'd rather handle financial conversations in Spanish.
Book a free consultation or learn more about our bookkeeping services.