At the end of the month someone opens a spreadsheet, scrolls through a few calendars and tries to remember what the team worked on. A client call here, an afternoon of revisions there. Some of it makes it onto the invoice. Some of it quietly does not.
For any business that sells its time, unbilled hours are the most common leak in the revenue. The work was done and the client would have paid for it, but nobody recorded it in a way that reached the invoice. The fix is not a harder push at month end. It is a simple routine: decide what is billable, set the rates, capture time as you go, approve it, and invoice from what was approved. This guide walks through each step.
Decide what counts as billable
Before anyone starts a timer, agree what the client pays for. Client meetings, the work itself and the revisions they ask for are usually billable. Internal admin, training and time spent fixing your own mistakes usually are not. Travel, research and quick phone calls are where teams disagree, so settle them up front.
Write the answer into the engagement letter or proposal, along with how you round time. Many firms bill in 6 minute increments, a tenth of an hour. Others use 15 minutes. Smaller increments are more accurate, larger ones are simpler to record, and either is fine as long as the client agreed it and you apply it consistently.
Set your rates before the work starts
Rates usually depend on who does the work and what kind of work it is. A senior consultant costs more per hour than a junior one, and some firms charge differently for strategy, delivery or support. Put the rates in one place rather than in people's heads, and agree them with the client in writing.
Rates change. When they do, give the new rate a start date, so work done before the change is still billed at the old rate. Updating a number in a spreadsheet halfway through a month is how invoices end up wrong in both directions.
Capture time as you work
Time recorded at the end of the week is an estimate. Time recorded at the end of the month is a guess, and guesses tend to be low. Short tasks, quick calls and small fixes are the first things forgotten, and they add up.
- Use a timer for focused work. Start it when you begin and stop it when you finish.
- Log short tasks the same day. A two minute entry at the end of the day beats trying to rebuild the week on Friday.
- Describe the work in the client's language. "Revised homepage copy after feedback" tells the client what they paid for. "Work on project" invites a question.
- Mark each entry billable or not. Recording non-billable time too shows where the hours really go.
Review and approve timesheets every week
A weekly timesheet review is the single best defence against billing mistakes. Each person submits their week, and a manager approves it or sends it back with a question. Missing days, entries on the wrong client and descriptions nobody understands get fixed while the work is still fresh.
Approving weekly also spreads the effort. Nobody spends the last day of the month reconstructing four weeks of work, and the invoice run becomes a matter of billing what has already been checked.
Turn approved time into a clear invoice
A single line that says "Consulting services, 42 hours" asks the client to trust you. An invoice that lists each piece of work, with the date, the type of work, a short description, the hours and the rate, shows them exactly what they paid for. Detailed invoices get paid faster because there is less to query.
Keep track of which hours have been invoiced. Once an entry is on an invoice it should be marked as billed, so it can never appear on the next one. Billing the same hour twice is rare, but it is embarrassing, and the correction costs you more goodwill than the hour was worth.
Send the invoice and get paid
Invoice on a fixed day, whether that is the first working day of the month, every Friday or at each project milestone. Clients learn when to expect it and you stop letting unbilled time build up. State the payment terms on every invoice, and make paying easy: an invoice that can be paid online by card in a minute gets paid sooner than one that needs a bank transfer set up.
Then watch what happens next. Knowing that a client has opened an invoice, and which invoices are past their due date, lets you chase early and politely rather than discovering a problem two months later.
Common mistakes
- Billing from memory. Reconstructed timesheets undercount, and the hours that go missing are real revenue.
- One vague line per invoice. A lack of detail invites questions and delays payment.
- Invoicing late. The longer the gap between the work and the invoice, the harder it is for the client to remember why it took so long.
- Out of date rates. Rate changes applied mid month without a start date bill some work at the wrong price.
- Double billing. Without a record of what has been invoiced, the same hours can slip onto two invoices.
How this works in Wizard Application
Wizard Application keeps time, timesheets and invoices in one place, so the routine above runs without spreadsheets in between.
Team members start a timer or add time by hand, and mark each entry billable. Rates are set per group and per type of work, with the date each rate takes effect, and they are applied to entries automatically so nobody has to look up a price. Entries roll up into weekly timesheets that move from Draft to Submitted and then to Approved, or back to the person as Rejected with a reason to fix it. Timesheets billed to a customer can be sent to them to sign off and pay online.
When it is time to bill, you create a draft invoice from a customer's unbilled billable time in one step. Each time entry becomes its own line, showing the date, the type of work, the description, the hours and the rate, and each entry is marked as invoiced so it cannot be billed again. Invoices are tracked as Draft, Sent, Viewed, Paid or Overdue, and with Stripe connected your customers can pay them online by card.
If you are still juggling hours in a spreadsheet, our guide to the signs your business has outgrown spreadsheets covers what else moves across with them. Consultancies, agencies and law firms can see how the pieces fit together for them on the consultancy, digital agency and law firm pages.
A checklist for billing your time
- Agree with each client what is billable and how time is rounded.
- Set rates per person or role and per type of work, with start dates.
- Record time as the work happens, with descriptions a client understands.
- Mark every entry billable or non-billable.
- Review and approve timesheets every week.
- Invoice from approved time only, one clear line per piece of work.
- Mark invoiced time so it is never billed twice.
- Invoice on a fixed day, with payment terms and an easy way to pay.
- Chase overdue invoices early.
Frequently asked questions
How often should we invoice for time?
Monthly suits most client work. Weekly or at milestones keeps cash flowing on long projects. Whatever you choose, invoice from approved timesheets on a fixed day.
Should we bill in 6 or 15 minute increments?
Either works if you agree it with the client up front and apply it consistently. Smaller increments are more accurate. Larger ones are simpler to record.
How do we avoid billing the same hours twice?
Invoice only from approved time, and mark each entry as invoiced once it is on an invoice. Wizard Application does this automatically.
Ready to stop leaking billable hours? Take a look at time tracking, timesheets and invoicing. Every paid plan comes with a 7 day free trial, so you can run a real month of billing through it before you commit.
