Running a construction or trade business in Perth involves more than completing projects and managing workers. Business owners must also track project costs, manage subcontractor payments, monitor cash flow and meet Australian taxation requirements.

For builders, electricians, plumbers and other trade professionals, financial management can become complicated when multiple projects are running simultaneously.

Materials may need to be purchased before customers pay, subcontractors may work across several jobs, and unexpected expenses can reduce project profitability.

Construction business accounting involves tracking the income, expenses, cash flow and financial performance of individual projects while meeting relevant tax and reporting obligations.

Reliable accounting helps business owners understand whether their projects are profitable and whether sufficient cash is available to support ongoing operations.

This guide explains the key accounting responsibilities for Perth construction and trade businesses, including job costing, GST, BAS, subcontractor reporting and practical financial management.

Why Is Accounting Important for Construction and Trade Businesses?

Construction accounting differs from many other types of small business accounting because revenue and expenses are often associated with individual jobs or contracts.

A construction company may operate several projects with different budgets, payment schedules and subcontractor arrangements.

Without accurate project-level records, business owners may struggle to identify which jobs generate profits.

Common Financial Challenges

Construction and trade businesses frequently manage:

Large upfront material expenses.
Multiple subcontractor payments.
Customer progress claims.
Retention amounts under contracts.
Equipment purchases and maintenance.
Unpredictable project delays.
GST and BAS responsibilities.
Irregular cash flow.

Accurate accounting provides information to help owners monitor these issues and make informed business decisions.

1. Track Project Costs With Job Costing

Job costing is one of the most important accounting practices for construction businesses.

It involves recording the income and expenses associated with individual projects.

Rather than combining all costs into one general category, job costing allows a business to evaluate the financial performance of each contract.

What Costs Should Be Included?

Typical project costs may include:

Direct labour: Wages and other directly attributable labour costs for employees working on a project.

Materials: Timber, concrete, electrical supplies, plumbing materials and other project-specific purchases.

Subcontractors: Payments to external contractors providing relevant services.

Equipment: Project-related equipment hire and appropriately allocated equipment costs.

Overheads: Indirect expenses allocated using a reasonable method where appropriate.

Example: Job Costing for a Perth Construction Project

Consider a hypothetical residential renovation project with the following figures, excluding GST.

Project item	Amount
Contract revenue	$150,000
Materials	$45,000
Direct labour	$35,000
Subcontractors	$30,000
Equipment and allocated overheads	$15,000
Total project costs	$125,000
Estimated project profit	$25,000

The estimated project margin is approximately 16.7%.

These figures assume the relevant revenue and project costs have been recognised appropriately and exclude other business-level expenses not allocated to the project.

Job costing helps the owner understand how individual cost categories affect profitability.

If material or labour expenses increase, the project margin may decline.

2. Manage Progress Payments and Customer Invoices

Construction projects are often completed over several weeks or months.

Instead of receiving full payment at the end, contractors may invoice customers at agreed milestones.

These payments are commonly referred to as progress payments or progress claims.

Why Progress Payment Tracking Matters

A construction company may incur substantial expenses before receiving the next contractual payment.

Accurate records can help track:

Contract values.
Approved variations.
Progress claims issued.
Payments received.
Outstanding customer balances.
Retention amounts.
Remaining project commitments.

Example: A Perth Building Contractor

Imagine a contractor working on a six-month renovation.

The business needs to purchase materials and pay subcontractors during the first month, but the next customer payment is due after a later project milestone.

Even if the contract is expected to be profitable, the business may experience temporary cash pressure.

Monitoring progress payments and expected expenses helps identify these timing differences.

Important: GST and accounting treatment of progress payments and retention amounts can depend on the contract terms and applicable rules. Business owners should not assume the full accounting treatment from the payment schedule alone.

3. Understand GST and BAS Requirements

GST and Business Activity Statements are important compliance responsibilities for many Perth construction and trade businesses.

Most Australian businesses generally must register for GST when their GST turnover reaches or is expected to reach $75,000, subject to relevant exceptions.

GST-registered businesses generally need to account for GST on taxable supplies and may claim eligible GST credits.

Common GST Considerations for Tradies

Construction businesses should review:

GST on taxable building services.
GST treatment of materials and equipment.
Eligible credits for business purchases.
Correct tax invoice information.
GST on progress claims.
Contract variations and adjustments.
BAS reporting obligations.

For example, when a GST-registered electrician invoices a customer $2,200 for a fully taxable service, the amount ordinarily includes $200 GST.

However, the actual GST treatment depends on the transaction and relevant circumstances.

Incorrect GST classification can affect reported liabilities and credits.

4. Keep Accurate Records of Subcontractor Payments

Subcontractors are commonly used by construction and trade businesses.

A builder may engage electricians, plumbers, plasterers, painters and other specialists to complete different parts of a project.

These arrangements create important financial record-keeping responsibilities.

What Subcontractor Information Should Be Recorded?

Businesses should maintain appropriate information such as:

Contractor names and business details.
Australian Business Numbers.
Invoices and payment records.
Relevant GST amounts.
Services performed.
Project allocations.
Applicable contract information.

These records support job costing and may be required for tax reporting.

What Is the Taxable Payments Annual Report?

The Taxable Payments Annual Report (TPAR) is an ATO reporting requirement that applies to certain businesses making payments to contractors for specified services.

Businesses primarily operating in building and construction may need to report relevant payments to contractors and subcontractors.

Where required, the TPAR is generally due by 28 August each year.

The requirement depends on the business's activities and applicable reporting rules.

ATO taxable payments reporting guidanceBusiness owners should review current to determine whether they must lodge.

Why TPAR Records Matter

Incomplete subcontractor payment records can create difficulties when preparing the annual report.

Businesses should consider identifying relevant payments throughout the financial year rather than trying to reconstruct the information at lodgement time.

5. Improve Cash Flow Management for Construction Projects

Cash flow management is especially important in construction because the timing of project expenses may differ from customer payments.

Businesses often need to fund materials, wages and subcontractors before receiving progress claims.

Common Cash Flow Challenges

Construction businesses may experience cash pressure due to:

Delayed progress payments.
Unexpected project variations.
Increased material prices.
Customer disputes.
Equipment repairs.
Retention arrangements.
Multiple projects requiring simultaneous funding.

Prepare a Project Cash Flow Forecast

A cash flow forecast estimates when the business expects to receive money and when payments will become due.

For construction companies, forecasts may be prepared for individual projects and the business overall.

Important information includes:

Expected progress claim receipts.
Supplier payment dates.
Subcontractor invoices.
Employee wages.
Equipment expenses.
Tax and superannuation obligations.

Forecasting can help identify funding gaps before they affect project delivery.

6. Manage Equipment and Vehicle Expenses

Construction and trade businesses often rely on vehicles, tools, machinery and specialist equipment.

These assets can involve substantial purchase and maintenance costs.

Business owners should understand how equipment purchases affect financial statements, cash flow and taxation.

Important Accounting Considerations

Relevant costs may include:

Equipment purchases.
Equipment hire.
Fuel and servicing.
Repairs and maintenance.
Insurance.
Financing and loan interest.
Depreciation.

Not every purchase is immediately deductible for income tax purposes.

Some assets are subject to depreciation rules, while eligible businesses may qualify for specific concessions.

The treatment depends on the relevant income year, eligibility conditions and business use.

A tax adviser can explain applicable requirements before major purchases are made.

7. Monitor Construction Project Profitability

A construction company can generate substantial revenue while earning relatively low margins.

For this reason, project-level profitability should be reviewed throughout the job rather than only after completion.

Financial Indicators Worth Monitoring

Indicator	Why it matters
Estimated project margin	Shows expected profitability
Actual project costs	Identifies spending against budget
Cost to complete	Estimates remaining project expenditure
Outstanding progress claims	Highlights expected customer receipts
Subcontractor commitments	Tracks future project payments
Cash flow forecast	Identifies potential funding shortages

Why Budget Versus Actual Reviews Matter

Suppose a Perth renovation project originally budgets $40,000 for materials.

As work progresses, the actual cost rises to $48,000.

Without reviewing the project budget, the owner may not immediately recognise the effect on profitability.

Regular cost reviews help identify variations and determine whether further action or revised forecasting is necessary.

8. Use Accounting Software Effectively

Accounting platforms such as Xero, MYOB and QuickBooks can assist with general bookkeeping, invoicing and financial reporting.

Some businesses also use specialist project-management or job-costing software.

However, software selection should reflect the size and complexity of operations.

Features Construction Businesses May Need

Useful features can include:

Job or project tracking.
Invoice management.
Bank reconciliation.
GST reporting.
Expense categorisation.
Supplier and subcontractor records.
Financial reports.
Integration with suitable project systems.

Software does not automatically prevent accounting errors.

Incorrect job allocation or GST coding can still produce unreliable financial information.

Regular reviews remain important.

9. Common Accounting Mistakes Perth Tradies Should Avoid

Several accounting problems can reduce visibility over project performance.

Not Tracking Costs by Job

When project costs are combined, it becomes difficult to identify profitable and unprofitable contracts.

Underestimating Overheads

Project quotations may overlook indirect expenses such as administration, insurance, equipment and vehicle costs.

Poor Progress Payment Monitoring

Unpaid claims can create cash shortages even when projects are progressing.

Mixing Private and Business Expenses

This can complicate financial reporting and tax calculations.

Ignoring GST and Subcontractor Reporting

Incorrect BAS records or missing TPAR information can create compliance problems.

Not Updating Project Forecasts

Original estimates may become unrealistic when material prices, labour requirements or project timelines change.

Reviewing these issues regularly can improve financial organisation.

10. When Should Construction Businesses Seek Accounting Support?

Some smaller trade businesses manage routine bookkeeping independently.

However, professional assistance may become more useful when multiple projects, subcontractors and reporting obligations create additional complexity.

Consider accounting assistance if:

Job costing is unreliable.
Project profit margins are difficult to calculate.
Cash flow varies significantly between contracts.
BAS or GST requirements are becoming difficult to manage.
Subcontractor reporting obligations are unclear.
Equipment purchases involve substantial financial commitments.
The business is expanding or hiring employees.

business accounting services in PerthProfessional, such as those offered by Investax, can assist business owners with general accounting, financial reporting, business taxation and relevant advisory requirements.

Before engaging an accountant, construction businesses should confirm that the provider has the appropriate qualifications, tax registrations and experience for their particular needs.

Frequently Asked Questions

What is construction business accounting?

Construction business accounting involves recording financial transactions, tracking individual project costs, monitoring contract revenue, managing cash flow and meeting relevant financial reporting and tax obligations.

Why is job costing important for construction businesses?

Job costing helps contractors identify the income and expenses associated with each project. It provides information about estimated profitability and can help reveal cost overruns before work is completed.

Do Perth tradies need to register for GST?

Most businesses must register when their GST turnover reaches or is expected to reach $75,000, subject to applicable exceptions. Businesses below the threshold may be able to register voluntarily.

What is TPAR for construction businesses?

The Taxable Payments Annual Report is used by businesses subject to the relevant reporting rules to report payments made to contractors for specified services, including building and construction work.

Can an accountant help with construction cash flow?

Yes. An accountant can help prepare cash flow forecasts, review outstanding payments and analyse project expenditure. This can support planning but cannot guarantee improved financial outcomes.

What accounting software is useful for tradies?

Xero, MYOB and QuickBooks are among the accounting platforms used by Australian businesses. The best fit depends on transaction volume, job-costing requirements, payroll needs and software integrations.

When should a construction business hire an accountant?

Professional support may be useful when the business manages multiple projects, experiences cash flow difficulties, employs staff, makes substantial equipment purchases or faces complex tax and reporting requirements.

Conclusion: Build Stronger Financial Processes for Your Trade Business

Construction and trade businesses face financial challenges that differ from many other small businesses.

Project costs, progress claims, subcontractor payments, equipment expenses and cash flow timing all influence financial performance.

Accurate job costing helps owners understand individual project profitability, while reliable bookkeeping supports GST, BAS and other relevant reporting responsibilities.

Regular financial reviews can also help identify cost overruns, unpaid claims and upcoming financial commitments.

For Perth construction and trade businesses, effective accounting means understanding both the profitability of individual projects and the financial position of the business as a whole.

Maintaining organised records and obtaining appropriate professional guidance can support better financial management as operations develop.

Disclaimer: This information is general in nature and does not consider your individual circumstances. Taxation, contracting and reporting obligations vary. Seek advice from a suitably qualified accountant, registered tax practitioner or legal professional before making significant decisions.

Accounting for Perth Construction & Trade Businesses

Explore accounting tips for Perth construction and trade businesses, including project costs, cash flow, GST, subcontractors and financial reporting