How to Invoice Clients for Hourly Work

An hourly invoice is the last step in a chain that starts days or weeks earlier, at the moment the work actually happens. If the chain is weak anywhere along the way, the invoice suffers. Hours go missing because they were never captured. Line items get disputed because the descriptions are vague. Payment arrives late because the invoice went out late. The good news is that each link in the chain is fixable, and the fixes compound. This guide walks through the full workflow in seven steps: capture, review, round, describe, itemize, send, and follow up.

Step 1: Capture the time when the work happens

Everything downstream depends on this step. You cannot invoice an hour you never recorded, and time reconstructed from memory at the end of the week reliably understates what you actually worked. The client call you took in the car, the email thread you answered between meetings, and the fifteen minutes of revisions you squeezed in before lunch all tend to vanish when you rebuild your week on Friday afternoon. We wrote about the most common leaks in five ways billable time leaks out of your week, and the pattern is consistent: the work that happens away from a running timer is the work that never gets billed.

There are two ways to close the gap. The first is discipline: start a timer for everything, including the two-minute phone call. The second is automation. On Android, TrackTime captures client phone calls, SMS conversations, time spent in Gmail and Outlook, and drive time automatically, with your permission, and matches each entry to the right client. Either approach beats reconstruction, and our guide to capturing every billable hour covers both in depth. The point is that capture has to happen contemporaneously, because an invoice built on a reconstructed timesheet starts life incomplete.

Step 2: Review every entry before it touches an invoice

Raw tracked time is not invoice-ready time. Before anything reaches a client, sit down with the week's entries and make three decisions about each one. First, is it billable at all? Some captured time belongs to admin, marketing, or a fixed-fee project. Second, is it attributed to the right client and matter? A misfiled entry is worse than a missing one, because it can appear on the wrong client's invoice. Third, is the duration honest? If you left a timer running through lunch, trim it now.

Do this review weekly rather than monthly. A week-old entry is still fresh enough to remember and correct. A month-old entry is a guess. If your tracking tool feeds a dashboard, the review can take fifteen minutes; TrackTime, for example, puts every captured entry in the web dashboard for exactly this review-and-adjust pass before billing.

Step 3: Apply your rounding rules, and apply them consistently

Most hourly professionals bill in increments rather than raw minutes. Lawyers typically use six-minute increments, which are tenths of an hour, so an eleven-minute call bills as 0.2 hours. Consultants and freelancers often use fifteen-minute increments. Whatever you choose, three rules keep it defensible:

• Pick one increment and state it in your engagement terms. Clients accept rounding when they agreed to it up front. They dispute rounding they discover on an invoice.
• Round each task the same direction every time. Rounding up is the common convention, but the convention only survives scrutiny if it is applied uniformly, not opportunistically.
• Do not round twice. Round each entry once, at invoicing time, from the actual recorded duration. Rounding at capture and again at invoicing quietly inflates the bill.

Step 4: Write descriptions the client can recognize

The description is the part of the line item the client actually reads, and vague descriptions are the single most common trigger for disputes. "Consulting services, 3.5 hours" invites a phone call. A description the client recognizes closes the question before it is asked.

A reliable formula is activity plus subject plus purpose. "Reviewed draft distribution agreement and marked up indemnification clauses for Thursday negotiation" tells the client what you did, what it concerned, and why it mattered. Compare that with "Document review," which tells them nothing. You do not need to write a paragraph. You need one complete sentence specific enough that the client remembers the work when they read it.

Two habits make good descriptions easy. Write them at review time, while the work is fresh, rather than at invoicing time. And let captured context do the heavy lifting: an automatically captured call already knows the contact, the date, and the duration, so all you add is the subject.

Step 5: Decide what to itemize and what to summarize

Not every entry deserves its own line. The goal of an invoice is clarity, and forty micro-entries can obscure as much as they reveal. A workable rule of thumb has three parts:

• Itemize anything substantial or anything the client participated in. Meetings, calls, deliverables, and any single block over about half an hour should each get a line, because these are the items the client remembers and checks.
• Summarize routine communication into a dated group. A line such as "Client correspondence, week of March 9: six emails and two brief calls regarding vendor onboarding, 1.1 hours" is honest, verifiable, and far easier to read than eight scattered six-minute lines.
• Never summarize across matters or projects. Each summary line should cover one client, one matter, and one bounded time period, so that the client can map it to their own records.

Keep the underlying detail even when you summarize. If a client questions the correspondence line, the strongest response is the full list of captured entries behind it, with dates, durations, and contacts.

Step 6: Build and send the invoice promptly

Invoices age badly. The longer the gap between the work and the bill, the fuzzier the client's memory of the work, and the slower the payment. Pick a fixed cadence, monthly at minimum and biweekly for larger engagements, and hold it. On the invoice itself, include the elements clients and their bookkeepers expect: an invoice number, the period covered, each line with date, description, hours, and rate, the increment policy stated once, the total, payment terms with a specific due date, and exactly how to pay.

Use the tool you already track time in if it can invoice, because every export and re-entry step between tracking and invoicing is a place where hours get lost or mistyped. TrackTime includes invoicing in the same dashboard where captured entries are reviewed, so the path from tracked hour to sent invoice has no copy-paste step in it. If your tracker cannot invoice, budget real time for the transfer and reconcile totals before sending.

Step 7: Follow up on schedule, not on frustration

Decide your follow-up sequence before you need it, and run it mechanically. A short, friendly reminder on the day after the due date resolves most late invoices, because most late invoices are oversights rather than refusals. A second notice a week later can restate the payment options and offer to answer any questions about line items. If an invoice goes a month past due, move the conversation to a phone call, and pause new work until the account is current. None of this needs to be adversarial. Professionals who invoice clearly and follow up predictably get paid faster precisely because there is never any drama in the process.

The workflow in one paragraph

Capture time when the work happens, automatically where possible. Review weekly, and make the billable, attribution, and honesty calls while memory is fresh. Round once, by a stated rule. Describe each item so the client recognizes the work. Itemize the substantial, summarize the routine, and keep the detail behind every summary. Send on a fixed cadence with clear payment terms, and follow up on a schedule. Every step is simple. The professionals who get paid well for hourly work are simply the ones who do all seven consistently.

Frequently asked questions

Should I round every entry up, and is that fair to clients?

Rounding up to a stated increment is the standard convention in hourly billing, and it is fair when the client agreed to the increment in advance and the rule is applied to every entry the same way. What is not defensible is inconsistent rounding, rounding the same entry twice, or splitting one continuous task into several entries so that each rounds up separately.

How much detail should invoice descriptions include?

Enough that the client recognizes the work without asking, and no more. One complete sentence covering the activity, the subject, and the purpose is usually right. Avoid both extremes: a bare label like "research" invites a dispute, while a paragraph of narrative buries the information the client actually wants.

How often should I invoice hourly clients?

Monthly is the floor, and biweekly is better for engagements with significant hours. Shorter cycles keep the work fresh in the client's memory, smooth your cash flow, and surface any disagreement about scope while it is still small. The one thing to avoid is an irregular cadence, because unpredictable invoices train clients to treat payment as unpredictable too.

What if I forgot to track some of the hours I worked?

Reconstruct what you can from evidence rather than memory: your call log, sent email, calendar, and message history all carry timestamps. Bill only what you can support, and treat the episode as a prompt to fix capture going forward. Automatic capture exists precisely so this situation stops happening; the entries are recorded whether or not you remembered a timer.

Stop losing hours before they reach the invoice

The best invoicing workflow in the world cannot bill an hour that was never captured. TrackTime records client calls, texts, email time, and drive time automatically on Android, stores metadata only, and turns reviewed entries into invoices in the same dashboard. Start a free 7-day trial and see how much of your week has been missing from your invoices, or learn how the Android app works.