LegalTimeTools

Time Increment Calculator

Convert worked minutes into billing increments under your firm’s rounding rule, and see what the rounding is worth.

Last reviewed

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Free · No sign-up · Runs in your browser

Legal time is billed in increments rather than in real minutes, and the increment plus the rounding rule together decide how a two-minute email becomes a line on an invoice. Six-minute units - tenths of an hour - are the most common convention, but they are a convention rather than a rule.

This calculator converts worked minutes into billable units under the rounding rule your engagement letter specifies, and reports the difference between the time worked and the time billed.

Your numbers

Results update as you type. Nothing is sent anywhere.

Result

Billable units

3

Billed hours

0.3

Value at your rate
$105.00
Minutes worked
13
Minutes billed
18
Rounding difference
5
Value per unit
$35.00
Units per hour
10

This tool performs arithmetic on the values you enter. It does not provide legal advice and does not create an attorney-client relationship.

Six-minute increments (tenths of an hour) are the most common billing unit, but the agreed increment belongs in the engagement letter.

Rounding every short task up adds real money across a year - and it is also the thing clients audit most closely. Use the rule your engagement letter states.

How to use the time increment calculator

  1. Enter the minutes actually worked on the task.
  2. Enter the billing increment your firm uses - six minutes is the usual default.
  3. Choose the rounding rule from your engagement letter.
  4. Read the billable units, the billed hours and the rounding difference.

What people use this for

  • Converting a timer reading into an invoice line.
  • Checking what a firm’s rounding convention is actually worth across a day.
  • Comparing six-minute increments against fifteen-minute ones.
  • Explaining the increment to a client who has queried an invoice.

Worked examples

Every figure below is produced by running this calculator against the example inputs, so the numbers always match the tool.

A thirteen-minute task, rounded up

Thirteen minutes at six-minute increments with a round-up rule, at $350 an hour.

Billable units
3
Billed hours
0.3
Value at your rate
$105.00

The same task, rounded to the nearest unit

Identical work under a round-to-nearest rule instead.

Billable units
2
Value at your rate
$70.00
Rounding difference
-1

Why six minutes

A tenth of an hour is easy to convert mentally and produces a defensible level of granularity. Fifteen-minute increments are simpler still and round far more aggressively - a two-minute phone call billed as a quarter of an hour is a seven-fold markup on the time actually spent.

The increment belongs in the engagement letter alongside the rate. A client who agreed to the rate but never saw the increment has a legitimate complaint when the arithmetic becomes visible.

Rounding is what clients audit

Across a year, rounding every short task up adds real money. It is also the first thing a sophisticated client or a fee auditor examines, precisely because it is systematic rather than occasional.

The defensible position is simple: state the increment and the rule in writing, apply them consistently, and be able to explain the arithmetic. Applying a round-up rule that was never disclosed is the version that causes problems.

Methodology and assumptions

What this calculator does, and what it deliberately does not do.

  • Units = minutes ÷ increment, then rounded up, down or to nearest according to the rule chosen.
  • Billed hours are units × increment ÷ 60. The rounding difference is billed minutes minus minutes worked.
  • The tool performs arithmetic or date counting on the values you enter. It does not interpret a rule, a statute or a contract.
  • Nothing you type is transmitted or stored - the calculation runs entirely inside your browser.

This website provides general informational and productivity tools and does not provide legal advice or create an attorney-client relationship.

The date and deadline tools count days exactly as you instruct them. They do not interpret court rules, statutes of limitation, filing requirements or any other legal authority, and they do not know the rules of your jurisdiction.

Always verify any date, fee, or calculation against the governing rule, the court calendar and your own professional judgement. If you need legal advice, consult a lawyer licensed in your jurisdiction.

Frequently asked questions

What is the standard billing increment?

Six minutes - a tenth of an hour - is the most common in commercial practice. Fifteen-minute increments still exist and round far more aggressively.

Is rounding up allowed?

It is the most common convention, and it should be disclosed in the engagement letter. Undisclosed rounding rules are where disputes come from.

Should I bill every short email?

That is a practice and client-relationship decision rather than an arithmetic one. Many firms have a policy of not billing very short administrative contacts at all.

Does this apply outside law?

The same arithmetic applies to any profession billing in increments - accountancy, consultancy, agency work. The six-minute convention is largely a legal one.

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