How to Invoice as an Independent Contractor (2026 Step-by-Step Guide)

You finished the job. Now you need to get paid. Sending a sloppy or incomplete invoice is the fastest way to delay that — clients push back, accountants ask questions, and you end up chasing money you've already earned. Here's exactly what goes on a professional independent contractor invoice, how to number it, and when you need to add tax.

TL;DR — 6 Things Every Contractor Invoice Needs

Your full legal name or business name and address
Client name and billing address
Unique invoice number (e.g. INV-001)
Invoice date and payment due date
Itemized services with rates and amounts
Total owing — including GST/HST if you're registered

What Every Independent Contractor Invoice Must Include

Missing a single field can hold up payment for days. Accounting departments have checklists — if your invoice doesn't match, it goes back to you. Here's what needs to be there, every time.

Building an invoice in Invoicito's generator, with a live sample-invoice preview (demo data shown).

Your full legal name or registered business name, plus your address. This is who the client is paying. If you operate under a business name, use that — not just your first name.

Client name and billing address. Use the exact legal name on the contract, not a nickname or a contact person's name. Wrong name = wrong entity = delayed or rejected payment.

A unique invoice number. Every invoice needs one. It's how both you and your client track payment status, and it's required if you're ever audited.

Invoice date and due date. Both. The invoice date establishes when the billing period starts; the due date tells the client exactly when you expect to be paid.

Itemized services with your rate and the amount per line. Don't just write "consulting services — $2,000." Break it down: 20 hours × $100/hr, or "Website redesign (flat fee) — $2,000." Clients approve line items, not lump sums.

Total amount owing, with tax as a separate line if applicable. Subtotal → tax → grand total. Clean, auditable, professional.

Invoice Numbering, Payment Terms, and Late Fees

Three things most contractors handle inconsistently. All three affect how fast — and whether — you get paid.

Pick a Numbering System and Stick to It

The simplest approach: start at INV-001 and go up from there. Alternatively, use a date-based format like 2026-06-001 (year-month-sequence). Either works. The rule is simple — never reuse a number, never skip one, and keep a running log. Gaps in invoice sequences are a red flag in any audit.

Net 15, Net 30, or Due on Receipt?

For most independent contractors, Net 15 or Net 30 is the right default. Net 15 means payment is due 15 days from the invoice date; Net 30 gives the client 30 days. Due-on-receipt works well for small one-off jobs where you're dealing directly with the owner. Larger corporate clients often default to Net 30 or even Net 45 — know your client before you invoice.

Close-up of a contractor invoice document on a desk with a pen and calculator, professional editorial photography, warm — Close-up of a contractor invoice document on a desk with a pen and calculator, professional editoria

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Invoices with a specific due date get paid faster than those with vague terms, contractors report — make the date impossible to miss

Late Fees: Get Them in Writing First

A late fee clause only works if the client knew about it before the job started. State it in your contractor agreement and repeat it on every invoice in the payment terms section. A standard rate is 1.5% per month (18% annually) on the outstanding balance — anything higher may not be enforceable depending on your province or state.

Key Takeaway:

Always state your late fee policy before you start work, not after the invoice is overdue. A surprise fee added to a final invoice won't hold up — and it damages the client relationship.

"I invoiced a landscaping client Net 30 for six months before realizing I'd never put a late fee clause in my contract. When they hit 60 days, I had nothing to enforce." — Marcus, self-employed landscaper in Ontario

HST/GST: When Independent Contractors Must Charge Tax

This is where a lot of contractors get tripped up — either charging tax when they don't have to, or not charging it when they absolutely must.

The rule in Canada: if your total worldwide taxable revenues exceed $30,000 in any single calendar quarter or over four consecutive quarters, you must register for GST/HST and begin collecting it. Below that threshold, registration is voluntary — you can still register early if you want to claim input tax credits on business expenses.

Did You Know?

Once you cross the $30,000 threshold, you must start charging GST/HST on the very next invoice — not at year-end. Waiting until your tax return is late registration and can result in penalties.

Revenue Situation	GST/HST Registration	Collect Tax on Invoices?
Under $30,000 threshold	Voluntary — your choice	Only if voluntarily registered
Over $30,000 threshold	Mandatory — required by law	Yes — starting on next invoice

Once registered, add your GST/HST registration number to every invoice and show the tax as a separate line item. Don't fold it into the subtotal — that creates headaches for your client's bookkeeper and yours.

Use a Free Independent Contractor Invoice Template

A professional invoice has three things working together: every required field filled in, clear payment terms the client can't misread, and correct tax treatment. Get all three right and you'll spend less time chasing payments and more time on billable work.

Ready-to-use. Pre-formatted with all six required fields, a tax line, and payment terms built in.

Download Free Contractor Invoice Template

Still deciding on Net 15 vs. Net 30? See our invoice payment terms guide for a side-by-side comparison.

The Bottom Line

Six fields are non-negotiable on every independent contractor invoice — missing one creates delays.
Use sequential numbering, pick a payment term (Net 15 or Net 30), and state your late fee before work starts.
In Canada, the $30,000 GST/HST threshold is hard — crossing it triggers mandatory registration on your very next invoice.
A clean template makes all of this automatic. Build your system once and it runs itself.

Frequently Asked Questions

What information is required on an independent contractor invoice?

At minimum: your legal name and address, client name and address, a unique invoice number, invoice date, due date, itemized list of services with rates, and the total amount owing. If you are registered for GST/HST, include your registration number and the tax amount as a separate line item — never folded into the subtotal.

How should an independent contractor number their invoices?

Use a simple sequential system starting at INV-001, or a date-based format like 2026-06-001. The non-negotiable rule: never reuse a number and never skip numbers. Consistent numbering makes payment tracking easy and is expected if you are ever reviewed by the CRA or IRS.

Can I charge a late fee on an unpaid contractor invoice?

Yes, but the late fee must be disclosed in writing before work begins — ideally in your contract and repeated in the payment terms section of every invoice. A standard rate is 1.5% per month (18% annually) on the outstanding balance after the due date. Adding a fee retroactively, after the invoice is already overdue, is difficult to enforce and damages the client relationship.

How to Invoice as an Independent Contractor: Step-by-Step with Template