Hourly and fixed-price work call for different invoice structures. Here's how to handle each correctly.
Invoicing hourly work
List the hours worked, the rate, and ideally a brief description of tasks completed during that period. Some clients expect a time log or summary attached alongside the invoice for transparency.
Invoicing fixed-price work
Rather than showing hours, list the deliverables agreed upon — for example, 'Website homepage design — flat rate.' The client is paying for the outcome, not the time spent, so the invoice should reflect that.
Handling scope changes on fixed-price work
If additional work falls outside the original fixed scope, invoice it as a separate line item clearly labeled 'Additional scope' or 'Change request,' rather than quietly folding it into the original price.
Mixing both on one invoice
Some projects include a fixed-price base with hourly add-ons (like revisions beyond an agreed limit). In that case, separate the two clearly with their own subtotals if needed.
Which model gets paid faster?
Fixed-price invoices are often processed faster since the client already knows and agreed to the number. Hourly invoices can trigger more questions if the final total varies from expectations, so clear time breakdowns help.
Choosing the right model going forward
Fixed pricing rewards efficiency and gives clients cost certainty; hourly pricing protects you against scope creep on less-defined projects. Many freelancers use fixed pricing for well-scoped work and hourly for ongoing or exploratory engagements.