The short version
- Export the period you are billing.
- Remove anything that isn’t billable.
- Group the entries that belong to the same piece of work.
- Add up each group and convert the time to decimal hours.
- Write one sentence for each group, in the client’s words.
- Multiply by your rate, total it, and add the due date and how to pay.
1. Export the period
Most time trackers export a period as a spreadsheet or CSV file, with a row for each entry: a date, a description and a duration. Export exactly the dates you are billing. An invoice that overlaps the last one is the quickest way to an argument.
2. Remove what isn’t billable
Your own bookkeeping, time spent learning a tool, a break you forgot to stop the timer for. If your tracker marks entries as billable or not, filter on that first.
3. Group entries into pieces of work
A tracker records every time you started and stopped. The client thinks in tasks. Two entries on the same task become one line. Here is a week of entries and the lines they turn into:
| In the timesheet | On the invoice | Hours |
|---|---|---|
| Nov 02, 1:30: Kickoff call | Nov 2: Kickoff call to agree the scope and who to interview. | 1.5 |
| Nov 03, 3:00: Stakeholder interviewsNov 03, 0:45: Interview notes | Nov 3: Stakeholder interviews, and a write-up of the notes. | 3.75 |
| Nov 04, 2:15: Process map - order intake | Nov 4: Mapped the current order-intake process. | 2.25 |
| Nov 05, 2:00: Findings deck | Nov 5: Wrote the findings and recommendations deck. | 2 |
| Nov 06, 1:00: Readout w/ ops team | Nov 6: Presented the findings to the operations team. | 1 |
Six entries became five lines, and the total is unchanged at 10.5 hours.
4. Convert the time to decimals
Trackers show time as hours and minutes. An invoice multiplies hours by a rate, so it needs decimals: divide the minutes by 60.
| Time | Decimal hours |
|---|---|
| 15 minutes | 0.25 |
| 30 minutes | 0.5 |
| 45 minutes | 0.75 |
| 1 hour 15 minutes | 1.25 |
| 2 hours 45 minutes | 2.75 |
The hours to decimal converter does a whole list at once and adds it up.
5. Write one sentence per line
Timer descriptions are notes to yourself: “Findings deck”, “Readout w/ ops team”. Rewrite each as what the client got: “Wrote the findings and recommendations deck”, “Presented the findings to the operations team”. Put the date first. There are more examples in how to describe your work on an invoice.
6. Rate, total, due date, how to pay
Multiply each line’s hours by your rate, add the lines, and finish the invoice with a due date and the ways you take payment. The full list of what an invoice needs is in how to write an invoice.
Having it done for you
Sandglass does steps two to five. You upload or paste the export, and it reads each entry’s date, description and duration, leaves out entries marked not billable, offers the tracked total as your hours, and drafts one dated line per piece of work. You check the draft and change anything before it is sent.