Law firms bill in tenths of an hour (6-minute increments). A 0.1-hour unit is the standard, and most firms round up any started increment — CEILING turns raw minutes into a billable tenth.
The example
14 minutes of work.
| A | B | |
|---|---|---|
| 1 | Item | Value |
| 2 | 14 min → hrs | 0.2333 |
| 3 | Billable tenths | → 0.3 |
The formula
The formula:
How it works
How it works:
- Divide minutes by 60 to get decimal hours.
- CEILING(…, 0.1) rounds up to the next tenth — the standard firm convention.
- For nearest tenth instead of always up, use
MROUND(hours, 0.1). - Multiply the billable tenths by the hourly rate for the line-item fee.
Round up vs round nearest is a billing-policy choice. CEILING bills any started 6-minute block as a full tenth (7 minutes → 0.2), which most firms use; MROUND bills the nearest tenth (7 minutes → 0.1). The difference adds up across hundreds of entries, so match the formula to the engagement letter — and disclose the convention to the client.
Try it: interactive demo
Minutes worked.
Variations
Nearest tenth
Round to closest:
Quarter-hour billing
Some firms use 0.25:
Line-item fee
Tenths × rate:
Pitfalls & errors
Up or nearest? CEILING always rounds up; MROUND rounds to the closest tenth.
Hours, not minutes. Divide by 60 first — CEILING works on the decimal hours.
Match the engagement letter. Bill in the increment the client agreed to.
Practice workbook
Frequently asked questions
How do I round billable time to tenths of an hour in Excel?
What's a tenth of an hour in minutes?
How do I round to the nearest tenth instead of up?
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