An hourly invoice should let the client verify the charge without reading every private work note. It connects three records: the engagement terms, the approved timesheet, and the final invoice.

Complete the review before creating invoice lines. Correct duplicates, confirm billable status, check rate categories, and obtain required approvals. Changing the source after invoicing makes later questions harder to resolve. Preserve the reviewed version so any later correction can be traced to the invoice and explained to the client.

Reconcile the time record

Select entries from the correct client, project, and billing period. Remove duplicate timers, complete missing descriptions, and confirm that every included activity is covered by the agreement.

Check project caps, retainers, included hours, and previous invoices before billing. The uninvoiced total should represent new, approved work rather than all time ever recorded on the project.

  • Filter the correct billing period
  • Review billable status and approvals
  • Remove duplicates and overlaps
  • Exclude previously invoiced time

Calculate hourly charges

Multiply the approved duration by the agreed rate for each service or role. Apply the billing increment and rounding policy consistently, then sum the line totals and verify the arithmetic.

Handle discounts, retainers, taxes, and reimbursable costs as separate, clearly labeled calculations. Do not change an hourly rate on the invoice unless the client has already accepted that rate.

  • Use the accepted rate
  • Apply one consistent time increment
  • Calculate each line independently
  • Separate discounts, taxes, and expenses

Write useful invoice line items

Group entries according to the detail promised to the client. A line can represent a service, phase, role, or date range as long as the client can understand what was delivered.

For each line, show the description, hours, rate, and amount. Add the project name and service period, and avoid vague labels such as “miscellaneous work” or unexplained blocks of time.

  • Name the service or project phase
  • Show hours and hourly rate
  • State the service period
  • Use descriptions tied to outcomes

Send and preserve supporting records

Add the invoice number, issue date, due date, payment method, and agreed payment terms. Attach or link the client-facing timesheet when required, while keeping private internal notes out of the shared document.

After sending, mark the source entries with the invoice number and preserve the approved version. Track payment against the invoice rather than editing billed hours to reflect when money arrives.

  • Include number and payment terms
  • Attach agreed supporting detail
  • Mark time entries as invoiced
  • Keep the approved source record

Frequently asked questions

Questions about how to invoice for hours worked

How much timesheet detail should accompany an invoice?

Provide the detail required by the agreement and enough information to verify the charge. Keep internal comments and unrelated client information private.

Can several hourly rates appear on one invoice?

Yes. Use separate lines for each service or role and show the corresponding hours and accepted rate clearly.

What if the hours exceed the estimate?

Explain the difference and obtain approval before continuing beyond an agreed cap. Do not surprise the client with unapproved excess hours on the final invoice.