How to Invoice for Hours Worked: A Freelancer's Guide to Time-Based Billing

You finished the project. The client's happy. Now you need to get paid. Knowing how to invoice for hours worked correctly — task-level detail, consistent rounding, zero ambiguity — is what separates freelancers who collect on time from those who spend weeks chasing payment. Vague hourly invoices invite disputes. Clear ones get paid.

Here's exactly what goes on each line, how to handle the awkward 1 hour 40 minutes you logged on Tuesday, and the five-step workflow that takes you from time tracker to sent invoice.

What to Include on an Hourly Invoice (Six Non-Negotiables)

An hourly invoice needs six specific things to hold up when a client questions the bill. Miss any one of them and you've handed your client an easy excuse to delay.

• Invoice date and invoice number — numbered sequentially (INV-001, INV-002) so both parties can reference them without confusion
• Your name/business and the client's name and address
• Itemized task descriptions with hours per task — one line per task, never a lump sum
• Your hourly rate — stated clearly on each line
• Line totals and a grand total
• Payment terms — Net 15 or Net 30, with accepted payment methods listed

Itemization is where most freelancers get it wrong. "8 hours — October work" is a dispute waiting to happen. "Homepage redesign (wireframes + revisions)" tells the client exactly what they bought. One describes effort; the other describes value.

Task Description	Hours	Rate	Total
Homepage wireframes	3.00	$75.00	$225.00
Client feedback revisions	1.75	$75.00	$131.25
Mobile responsive QA	2.25	$75.00	$168.75
Subtotal			$525.00

Rounding, Partial Hours, and Overtime: The Rules Nobody Explains

You worked 1 hour and 40 minutes. What do you bill? Three legitimate methods exist — and which one you pick matters far less than using it without exception.

"Your rounding method wasn't the problem. The silence was."

A $47 dispute that could have been avoided with one sentence in the contract.

Consider James — a scenario we see regularly — a UX consultant in Toronto who billed exact minutes for three months, then switched to 15-minute rounding on invoice four without mentioning it. The client disputed $47. The method wasn't the issue; the undisclosed change was. Pick one method, state it in your contract or on the invoice itself, and never switch mid-project.

On overtime: freelancers have no legal overtime rate the way employees do. It only applies if your contract specifies it — for example, "work requested outside business hours billed at 1.5x." If it's not in writing, bill your standard rate.

From Time Tracking to Sent Invoice in Five Steps

The biggest invoicing mistake isn't formatting. It's logging hours from memory at the end of the week. Your totals will always come out low. Track as you work.

1. 1 Track time per task as you work — use a timer app or note start/end times. Never reconstruct from memory on Friday afternoon.
2. 2 Tally hours by task at invoice time — group entries by task, not by day. Three separate "research" blocks become one line.
3. 3 Build the invoice with one line per task — description, hours, rate, line total. If you bill recurring clients, a freelance invoice template saves significant time here.
4. 4 Add subtotal, HST if applicable, and total due — tax as its own line, never folded into the rate.
5. 5 Send with a due date and payment method stated clearly — "Payment due Net 15 via bank transfer or credit card." No ambiguity, no follow-up questions.

Frequently Asked Questions

How do I calculate the total on an hourly invoice?

Multiply the hours worked per task by your hourly rate to get each line total, then sum all line totals for the subtotal. If you're a Canadian freelancer registered for HST, calculate the applicable HST percentage on the subtotal and add it as a separate line — the grand total is subtotal plus HST.

Should I round up hours on a freelance invoice?

Only if your contract says so — "round up" is not a universal freelance rule. The most common approach is rounding to the nearest 15 minutes, which is fair in both directions. Whatever method you choose, apply it consistently across every invoice and tell your client upfront. No surprises.

What's the difference between an hourly invoice and a fixed-price invoice?

An hourly invoice charges based on actual time spent, with each task itemized by hours and rate — the final amount isn't known until the work is done. A fixed-price invoice charges one agreed amount regardless of hours worked. Hourly billing suits ongoing retainers or variable-scope projects; fixed-price works better when deliverables are clearly defined from day one.

Do I need to include my business number on a Canadian freelance invoice?

Yes, once you're registered for HST, you must include your 9-digit GST/HST Business Number on every invoice that charges tax. Without it, your client can't claim an input tax credit. If you're under the $30,000 small supplier threshold and not yet registered, you don't charge HST and don't need a business number on the invoice.

Can I send a freelance invoice before the work is finished?

Yes — milestone invoicing is common and advisable on longer projects. Invoice at defined checkpoints (e.g., 50% through, or at the end of each week on a retainer). Just make sure your contract outlines the billing schedule so the client isn't surprised.