Billing by the hour is common for consultants, lawyers, designers, and trades. Here's how to structure, document, and invoice time-based work professionally.
When to Bill by the Hour
Hourly billing suits work where the scope is difficult to define upfront, where the time required varies significantly, or where clients want flexibility to adjust as the project evolves.
Common hourly-billed professions: consulting, legal, accounting, design, development, copywriting, photography, trades (plumbing, electrical, building), coaching.
The alternative — fixed-price billing — works when scope is clearly defined. Many businesses use both: fixed price for well-defined deliverables, hourly for open-ended or advisory work.
Tracking Your Hours
Accurate hourly invoicing starts with accurate time tracking. Methods:
Time-tracking app: Toggl, Clockify, and Harvest are popular free and low-cost options. Start a timer when you begin work, stop when you finish. The app logs billable hours per project and client automatically.
Spreadsheet timesheet: Date, client, project, hours worked, description. Simple and sufficient for lower volumes.
Physical timesheet: Works for trades who are on-site — note start time, end time, and task for each visit.
Whatever method you use, record hours the same day. Reconstructing a week of hours on Friday afternoon leads to under-billing and inaccurate records.
What to Include on an Hourly Invoice
Your invoice should show:
Hourly rate: Your agreed rate per hour (e.g. $120/hr)
Hours worked: Total hours billed — ideally with a breakdown by date or task
Time period covered: The date range the invoice covers (e.g. 1–31 May 2025)
Calculated total: Hours × Rate = Amount
Description: What the hours were spent on
Example line item:
"Digital marketing consultancy — 14 hours × $120/hr — May 2025 — $1,680"
For larger invoices or clients who want detail, provide a timesheet attachment or a line-by-line breakdown.
Providing a Timesheet with Your Invoice
For clients who require it (and for your own protection), attach a timesheet showing:
| Date | Description | Hours |
| 1 May | Strategy meeting — 2hrs |
| 3 May | Keyword research — 3hrs |
| 7 May | Content calendar creation — 4hrs |
This level of detail removes any ambiguity and makes disputes virtually impossible if the client approved the work.
Rounding and Minimum Charges
Decide upfront how you handle short time increments:
State your rounding and minimum charge policy in your initial agreement — not on the invoice after the fact.
Getting Approval Before Billing
For ongoing time-billed engagements, consider a monthly approval process:
This eliminates billing disputes because the client has signed off on the hours before the invoice arrives.
Capping Hourly Work
For clients who are nervous about open-ended hourly billing, offer a monthly cap: "I'll bill at $150/hr up to a maximum of 20 hours per month ($3,000). Any additional hours require your approval."
The cap gives the client budget certainty while preserving hourly billing flexibility for you.
Invoicing for Hours in Quotation Expert
In Quotation Expert, add a line item with the description of work, quantity (hours), unit price (your hourly rate), and the total calculates automatically. For clients who need a timesheet, attach it to the PDF or paste the breakdown in the description field. Your full invoice history by client shows all hourly billing over time — useful for performance reviews and rate negotiations.
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