Last updated November 6, 2026
To track billable hours, record each block of client work on the day you do it: the date, client, job, what you did and the minutes it took. Mark it billable or not, keep everything in one log, and close that log on a fixed day each week, while the details are still fresh.
What counts as a billable hour?
A billable hour is time you can charge to a client under the agreement you have with them. That usually means the work itself, plus the calls, emails and research the job needed. Quoting for new work, chasing invoices and fixing your own mistakes normally don't count.
The agreement decides, so the same task can be billable for one client and not for another. The grey areas are in the guide to billable vs non-billable hours.
What should a time log record?
A time log needs enough detail to build an invoice and to answer a client's question six weeks later. These columns work in a spreadsheet or in any tool:
| Column | Example | Why it's there |
|---|---|---|
| Date | 9 March 2026 | The invoice states the period, and every query starts with "when?" |
| Person | AK | Rates differ between people |
| Client | Client A | Who pays |
| Job | Stock review | Keeps two jobs for one client apart |
| Work done | Call with finance lead about variances | The client may read this |
| Minutes | 18 | The raw figure, before any rounding |
| Hours | 0.30 | What the invoice multiplies |
| Billable | Yes | Not every client hour gets charged |
| Invoice no. | INV-2026-0042 | Stops the same hours being billed twice |
The last column is the one people skip. Fill it in the day you invoice and you can filter the log to "billable, not yet invoiced" every month without thinking.
Write the description as if the client will read it, because one day they will. "Call with finance lead about variances" survives a query. "Admin" doesn't.
Which way of recording time is most accurate?
Noting the time as you finish each task is the most accurate method for most people, and rebuilding a week from memory is the least.
| Method | Works well for | Weak point |
|---|---|---|
| Running timer | Long stretches of desk work on one job | You forget to stop it, and short interruptions get swallowed |
| Note as you finish | Most people, most days | It needs a habit |
| End-of-day entry from calendar, sent mail and call log | Days full of small tasks | Quick calls disappear |
| End-of-week entry from memory | Nothing, if you can avoid it | You're guessing, and the entries look like it |
You don't need software to use any of these except the first. A notebook and a spreadsheet will do.
A weekly routine that keeps the log honest
- As you finish a task, note the minutes and a few words about it.
- At the end of each day, check your calendar, sent mail and call history for anything you missed.
- On Friday, fill the gaps and compare the hours logged with the hours you worked. If you worked 40 and logged 31, go and find the other nine.
- At month end, total by client and job, then turn the hours into an invoice.
If several people log time, a shared weekly layout saves a lot of chasing: see the team timesheet template. To total hours for each job, see tracking billable hours by project.
A worked example: one day in the log
Here's an invented example. A consultant who charges €90 an hour logs this Monday:
| Client | Job | Work done | Minutes | Hours | Billable |
|---|---|---|---|---|---|
| Client A | Stock review | Site visit, checked count sheets | 150 | 2.50 | Yes |
| Client A | Stock review | Call with finance lead about variances | 18 | 0.30 | Yes |
| Client B | Process map | Drafted the intake flow | 72 | 1.20 | Yes |
| Client B | Process map | Reworked the draft after our own error | 30 | 0.50 | No |
| Own firm | Sales | Wrote a quote for a new enquiry | 45 | 0.75 | No |
| Total | 315 | 5.25 |
Billable time is 150 + 18 + 72 = 240 minutes, which is 4.00 hours. At €90 that's €360 for the day. The other 75 minutes earn nothing, but they're worth seeing: rework and quoting took nearly a quarter of the logged day.
In a spreadsheet, with minutes in column D, the hours column is =ROUND(D2/60,2).
Why 1.30 isn't an hour and a half
Clock time typed as a decimal is the commonest arithmetic slip in a time log. One hour thirty minutes is 1.5 hours, not 1.30. At €90 an hour, 1.30 bills €117.00 and 1.5 bills €135.00, so that one entry loses €18.00.
Keeping a minutes column prevents it. It also keeps rounding out of the log. Round once, when you prepare the invoice, using the billing increment in your agreement.
The mistakes that lose billable time
- Ignoring anything under ten minutes. Twelve five-minute calls are an hour.
- Vague entries. "Client A, misc, 3 hours" gets queried, and queried hours often end up written off.
- Logging only hourly jobs. Fixed-fee work needs a log too, or you can't tell whether the fee paid. See budget hours vs actual hours.
- Deleting hours you won't bill. Mark them non-billable instead, so the record shows what the job really took.
Tracking billable hours in ERPFlow
ERPFlow doesn't have a timer or timesheets today, and time recorded on a card doesn't become invoice lines. Time tracking, including converting tracked time into invoices, is coming soon.
What exists now is a Time spent field on each card in Projects, typed as hours and minutes. Totals add up per project and per customer. That gives you a running figure for each job, with no billable flag, no date against the time and no split by person. If you bill by the hour, keep the detailed log above in a spreadsheet and use the card totals as a cross-check. The guide to logging time as a team member shows how the field behaves.
To bill the hours, add a line to an invoice and type them in as the quantity, usually from a service that holds your hourly price.