Contractor Invoicing in Ontario: What to Include (So You Don't Lose Money at Tax Time)

If you're a contractor in Ontario, your invoice is not “just paperwork.” It's what protects you when:

• a client disputes work,
• you need to prove income,
• you're claiming expenses,
• CRA ever asks questions,
• you're charging (and reporting) HST correctly.

Here's a clean, practical checklist you can copy.

The Ontario contractor invoice checklist (copy this)

1) Your business details (must-have)

Include:

• Your legal name / business name
• Business address (or mailing address)
• Phone number + email
• Website (optional)

If you're incorporated, use the corporation's legal name (not just your personal name).

2) Client details (must-have)

Include:

• Client's legal name / business name
• Client address (or at least city/province)
• A contact name (optional but helpful)

3) Invoice number + invoice date (must-have)

• Unique invoice number (no duplicates)
• Invoice date
• Service period (if different than invoice date)

This matters for clean bookkeeping and HST reporting.

4) Clear description of work (must-have)

Avoid vague lines like “contracting services.”

Better:

• “Drywall installation — basement renovation — 18 hours labour”
• “Electrical rough-in — kitchen — materials + labour”
• “Snow removal — 4 visits — Jan 1 to Jan 31”

5) Quantity, rate, and totals (must-have)

Show the math clearly:

• Hours × hourly rate
• Units × unit price
• Fixed price (with scope)

Then:

• Subtotal
• HST (if applicable)
• Total due

6) HST number (only if you're registered)

If you're registered for HST, include:

• Your HST/GST number (BN)
• HST amount charged

If you're not registered, don't charge HST and don't show an HST number.

7) Payment terms (must-have)

Include:

• Due date (e.g., “Due on receipt” or “Net 15 / Net 30”)
• Accepted payment methods (e-transfer, cheque, etc.)
• Late fee policy (optional)

8) Where to send payment (helpful)

• E-transfer email
• Cheque payable to
• Mailing address (if cheques)

9) Notes that protect you (optional but smart)

Examples:

• “Change orders billed separately”
• “Materials subject to availability”
• “Warranty terms: ___”
• “Deposit required before scheduling”

Common invoicing mistakes that cost contractors money

• No invoice numbers (bookkeeping becomes a mess)
• Vague descriptions (hard to defend if questioned)
• Charging HST when not registered (or not charging when you should)
• Mixing personal and business payments
• Not tracking deposits properly
• Not saving proof of payment (e-transfer screenshots, bank deposits)

Quick FAQ (Ontario contractors)