0.1 hour is 6 minutes

What are tenths of an hour?

A "tenth" is one-tenth of an hour, equal to exactly 6 minutes. When professionals say they bill "in tenths," they divide every hour into 10 equal increments rather than tracking minutes directly.

This creates a clean decimal system: 0.1 hours = 6 minutes, 0.5 hours = 30 minutes, 1.0 hours = 60 minutes. The decimal format makes multiplying time by hourly rates straightforward — no fraction conversion required.

Why do lawyers bill in 6-minute increments?

Many law firms use tenths because 6-minute increments are easy to review, easy to multiply by hourly rates, and familiar to clients who receive hourly invoices.

Three reasons professionals use this system:

1. Calculation simplicity — Decimal math is easier than fraction math. At $400/hour, 0.3 hours is exactly $120.
2. Minimum billing threshold — A quick phone call or email review still generates 0.1 hours ($40 at $400/hour). This ensures small tasks are compensated.
3. Readable invoices — Decimal entries are easier for clients, reviewers, and accounting systems to scan.

Today, tenths billing extends beyond law. Consultants, accountants, architects, and freelancers use the same system for consistent client billing.

How to convert minutes to tenths

The standard method is to round up to the nearest 6-minute increment. Any time within a 6-minute window rounds to that tenth.

Examples:

• 2 minutes → 0.1 tenths (rounds up to 6 min block)
• 6 minutes → 0.1 tenths (exactly one block)
• 7 minutes → 0.2 tenths (starts second block)
• 15 minutes → 0.3 tenths (rounds 15 up to 18)
• 45 minutes → 0.8 tenths (rounds 45 up to 48)

Rounding practices: What's ethical?

Rounding practices depend on your engagement terms, billing policy, and professional obligations. Keep entries reasonable and consistent:

• Don't bill minimum for every email — Multiple quick emails to the same client should be batched into one time entry.
• Consider fixed-fee alternatives — Routine tasks like document filing may warrant flat rates instead of hourly billing.
• Use accurate descriptions — Time entries should reflect actual work performed, not just category labels.

Professional-responsibility rules require legal fees to be reasonable. The safer habit is to describe work accurately, batch tiny tasks when appropriate, and avoid treating every small action as a separate minimum charge.

Alternatives to tenths billing

Some firms use different increment systems:

• Quarter-hour (0.25) — 15-minute increments. Less precise, potentially overbills small tasks.
• Twelfths (0.083) — 5-minute increments. More precise but creates awkward decimals.
• Actual minutes — Exact time tracking. Most accurate but requires fraction math for hourly calculations.

Tenths remains the dominant standard because it balances precision with calculation simplicity. A 6-minute minimum is small enough to avoid significant overbilling while large enough to compensate for task-switching overhead.

Why use a legal billing capture app?

Manual time tracking creates two problems: under-billing (forgetting to log time) and calculation errors (converting minutes incorrectly).

The larger risk is ordinary leakage: calls, emails, and quick review tasks that happen away from the desk and never make it into the monthly bill.

The Tenths app solves both problems. Timers run in the background so you never forget to track. Conversion is automatic: start, stop, and the app calculates tenths instantly. Export to PDF, Excel, or CSV for client invoicing.

Tenths replaces the timer, not your whole practice management system. It is for attorneys who need to capture billable work from the phone, not adopt another platform just to log a call.