Construction Accountant in Ontario
Remote CPA accounting for contractors, builders and construction trades across Ontario — including Whitby and the Greater Toronto Area.
An Ontario contractor charges 13% HST on a single registration, files a T5018 information return for subcontractor payments, and recognises holdbacks under the Construction Act's lien timelines — which run to different dates than Québec's.
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Key facts
| Sales tax | 13% HST on one GST/HST registration — no separate provincial registration |
|---|---|
| Subcontractor reporting | T5018, due six months after the reporting period end you elect |
| Holdback | Governed by Ontario's Construction Act lien and publication timelines |
| Corporate returns | Federal T2 only; Ontario corporate tax is administered by the CRA |
| Service model | Delivered remotely from Montréal — no Ontario office required |
A&S Financials provides construction accounting for contractors, builders and trades throughout Ontario, delivered remotely. From Whitby to the Greater Toronto Area, we handle the accounting that construction runs on — holdbacks, work-in-progress, T5018 subcontractor reporting and project-level job costing. Work with a CPA team that understands long project cycles and tight margins, without needing an office down the street. Everything is handled online so you can focus on the build.
Book a consultationHow we help
- Project and job-cost reporting
- Work-in-progress and holdback accounting
- T5018 subcontractor reporting
- Payroll for field and office staff
- GST/HST and progress-billing support
- Fully remote service across Ontario
Ontario is simpler than Québec on tax, and stricter on lien timing
On the tax side Ontario is the lighter jurisdiction. One HST registration covers the 13% rate, there is no separate provincial sales tax to track, and Ontario corporate income tax is administered by the CRA — so there is one corporate return rather than the two a Québec corporation files. The complexity moves to the construction side. Ontario's Construction Act sets its own timelines for holdback release, notice of publication of substantial performance, and the prompt payment and adjudication regime. Those dates decide when a holdback becomes receivable, which is what decides when it is taxable. Recognising holdback revenue on the Québec timeline, or on the invoice date, is the error we correct most often for contractors working across both provinces.
T5018 is the filing most contractors discover late
A business whose primary activity is construction must report payments to subcontractors on a T5018 information return. It is separate from the T4 regime, it applies to payments to corporations as well as individuals, and it is easy to miss because it is not part of the corporate tax return. The reporting period can be the calendar year or the fiscal year, elected once and then applied consistently, with the return due six months after the period end. The CRA matches T5018 data against the recipients' reported income, so under-reporting on the payer side draws attention to both parties. Late filing carries a per-slip penalty that scales with the number of slips and the delay.
Frequently asked questions
Do I need an accountant in Ontario, or can you work remotely?
What sales tax do I charge in Ontario?
When does an Ontario holdback become taxable?
Do I file an Ontario corporate return separately?
Speak with a Montréal CPA
Contact us to discuss your accounting and tax needs — in the language you prefer.