Construction Accounting for Subcontractors: The Basics

DEFINITION

job cost ledger

A subsidiary ledger tracking all costs (labor, materials, equipment, subcontractors) by individual job. Every expense is coded to a specific job and cost category. The job cost ledger is the source data for job profitability reporting and WIP schedule preparation.

DEFINITION

cash basis vs. accrual

Cash basis records income when received and expenses when paid — simpler, but masks the true profitability of open jobs. Accrual accounting records income when earned and expenses when incurred. Construction accounting requires accrual to accurately represent percentage-of-completion revenue and underbilling/overbilling positions.

DEFINITION

bonding

Surety bonds required for public and many commercial construction projects. Bonding companies review WIP schedules and financial statements when setting bonding capacity. Accurate construction accounting directly affects how much work a sub can bond, which determines what projects they can pursue.

DEFINITION

lien rights

The right to file a mechanic's lien against a property for unpaid work. Preserving lien rights requires proper documentation of work performed and amounts invoiced — construction accounting that tracks billing by job supports lien rights enforcement at closeout.

The Three Accounting Requirements That Differ for Subs vs. Standard Businesses

Most specialty trade subs start their business with QuickBooks set up the same way a retail store or service company would use it. That works fine for the first few years when projects are small, fast, and numerous. It starts breaking down when projects get larger, run longer, and the bonding company calls asking for a WIP schedule.

The three differences that matter:

Job-level cost tracking. A retail business tracks expenses by category — payroll, cost of goods, rent, utilities. A specialty trade sub has to track expenses by job. Every labor hour, every material purchase, every subcontractor invoice needs to be tagged to a specific project. Without this, the monthly P&L shows total profit or loss but can’t tell you which jobs made money and which jobs cost you money. After 10 active jobs, the inability to see this destroys your ability to manage the business.

Percentage-of-completion revenue recognition. Standard businesses recognize revenue when they sell something or deliver a service. Construction revenue is earned as work is performed on long-duration contracts. A $1.2M mechanical contract that’s 55% complete has generated $660,000 in earned revenue — regardless of what’s been billed and regardless of what’s been collected. Reporting only cash received on that contract understates revenue and makes the business look worse than it is; overbilling understates liabilities and makes it look better. Neither is accurate.

Balance sheet accounts specific to construction. Retainage receivable, retainage payable, underbillings, and overbillings don’t appear on a standard business balance sheet. For a specialty trade sub, these can represent significant dollar amounts. Retainage receivable on an active portfolio of $8M in contracts might be $400,000-$800,000. Underbillings might be $150,000. These are real assets that don’t show up if your books are configured for a retail business instead of a construction company.

The QuickBooks Gap — What It Handles and What It Misses

QuickBooks handles the general ledger functions fine: accounts payable, accounts receivable, payroll, bank reconciliation, and basic financial reporting. Specialty trade subs who use QuickBooks for bookkeeping and invoice their customers through it are not wrong — it’s a competent accounting system.

The gap shows up in three specific places.

WIP schedule generation. QuickBooks doesn’t produce a WIP schedule. Some accountants build one in Excel using QuickBooks data exports. This works, but it requires hours of manual work each month and creates a document that exists separately from the accounting system. When the bonding company asks for an updated WIP schedule on short notice, “we’ll have that to you next week after our accountant builds it” is not a good answer.

Cost-code level reporting. QuickBooks’ Projects feature tracks costs by job. It doesn’t track costs by phase or cost code within a job — labor for rough-in vs. trim-out, or materials for the mechanical room vs. the upper floors. That level of detail is what tells a PM whether a specific phase is running over budget before the whole job is lost.

Percentage-of-completion revenue recognition. QuickBooks doesn’t calculate percentage of completion and adjust revenue accordingly. A construction CPA can make manual journal entries each month to implement this, but it’s manual work that doesn’t scale.

When to Invest in Purpose-Built Construction Accounting Software

Three signals suggest it’s time to look beyond QuickBooks:

Your job portfolio has grown past 10 active jobs and you’re spending significant time each month assembling job cost reports from QuickBooks exports and spreadsheets. The manual process becomes a bottleneck that delays decisions.

Your bonding company has asked for a WIP schedule and you don’t have a clean one. Bonding capacity limits what projects you can pursue. If your accounting setup is the bottleneck on bonding, that’s a growth constraint with a direct cost.

You’ve had a job finish at a loss that you didn’t see coming. The early warning signals — labor trending over budget in week 3, materials coming in 15% high by mid-job — weren’t visible because the data wasn’t organized to surface them. After that experience, the cost of the software is easy to justify.

Purpose-built tools for specialty trade subs range from flat-rate tools at $20-$99/month (MarginLock, Knowify) to full construction ERPs at $115+/user/month (Sage 100, Foundation Software). The right entry point depends on revenue size, team size, and whether you need a job costing layer on top of QuickBooks or a full construction accounting replacement.