How to Track Billable Hours and Invoice Your Clients (Step by Step)
If you bill by the hour, the problem usually isn't tracking time itself — it's that logging it properly, organized by client and project, and then turning it into an invoice without re-entering everything by hand, requires a clear flow. This guide covers the 4 steps, with or without ProHours.
Step 1: Log every entry with client, project, and category from the first minute
The most common mistake is tracking time "in general" and trying to reconstruct who each hour belonged to at the end of the month. Every time entry should carry, at minimum:
- Client — who you're going to bill this to.
- Project — which specific piece of work within that client.
- Category — development, design, meetings, support, etc. (useful later for reporting and for deciding what's billable and what isn't).
- Billable or not — not all the time you work is time you charge the client for (internal meetings, for example).
In ProHours, this happens at the moment you create the entry (~3 seconds), not as a separate "organizing" step afterward.
Step 2: Apply multipliers when they apply
If you work overtime, weekends, or holidays at a different rate, mark it in the moment — don't calculate it by hand at the end. A 2x multiplier on a holiday, for example, needs to reflect automatically in that entry's billable total.
Step 3: Turn entries into a time sheet, and review it before invoicing
Before invoicing, group entries by client and period (a month, for example) into a time sheet. This step lets you:
- See total hours and the billable amount before sending it.
- Catch miscategorized entries or entries missing a client.
- If you work with a team, route the sheet through an approval flow (contributor → reviewer → owner) before it's ready to invoice.
Step 4: Generate the invoice without re-entering data
The most common friction point: exporting hours to Excel and then typing those same numbers by hand into another invoicing tool. If your time tracking app generates the invoice directly from the already-reviewed time sheet (PDF, with your rates and multipliers already applied), you skip that step — and the margin for error of mistyping a number.
Flow summary
- You log the entry with client, project, and category.
- You apply the multiplier if it applies.
- You group entries into a time sheet and review it (or send it for approval).
- You generate the invoice directly from there.
ProHours covers all 4 steps in a single tool, included on the free plan (30 time entries a month, no card required).