LegalCaseTools

Case Duration Calculator

Measure how long a matter ran and how intensively it was worked, in calendar days, business days and hours per month.

Last reviewed

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Free · No sign-up · Runs in your browser

Duration and intensity are different measures and they are routinely conflated. A matter can run for two years at four hours a month, or for three months at eighty - and those are completely different matters to staff, budget and price.

This calculator reports both, plus the effective rate the matter actually achieved. Run across a set of closed matters of the same type, it produces the most defensible fee estimate available to a firm: its own history.

Your numbers

Results update as you type. Nothing is sent anywhere.

Result

Duration in months

15.9

Hours per month

6

Calendar days
485
Business days
347
Years
1.33
Hours recorded
96
Fees billed
$31,000
Fees per month
$1,950
Effective rate
$322.92

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

Duration and intensity are different measures. A matter can run for two years at four hours a month, or three months at eighty.

Tracking hours per month across closed matters of the same type is the fastest way to build a defensible fee estimate for the next one.

How to use the case duration calculator

  1. Enter the date the matter opened and the date it closed.
  2. Enter the total hours recorded on it.
  3. Enter the fees actually billed.
  4. Read the duration, the intensity and the effective rate.

What people use this for

  • Building fee estimates from your own closed-matter history.
  • Understanding which matter types consume capacity unevenly.
  • Planning staffing across matters with different intensity profiles.
  • Reviewing whether a matter achieved the rate it was priced at.

Worked examples

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

A long, low-intensity matter

Opened 2 March 2026, closed 30 June 2027, with 96 hours recorded and $31,000 billed.

Duration in months
15.9
Hours per month
6
Effective rate
$322.92

A short, intensive matter

Opened 2 March 2026, closed 30 May 2026, with 180 hours recorded and $58,000 billed.

Duration in months
2.9
Hours per month
62.1
Fees per month
$20,000

Intensity is what staffing has to absorb

Two matters billing the same total behave completely differently in a practice. A long, low-intensity matter occupies a slot in the docket and consumes little capacity; a short, intensive one consumes a great deal of capacity in a narrow window and cannot be spread.

Hours per month captures that distinction. It is the figure to look at when deciding whether a practice can take on another matter of a given type this quarter.

Your own history beats any benchmark

Published data on how long matters take is general to the point of being unhelpful, because duration depends on jurisdiction, opponent, complexity and the client’s own decision-making speed.

Running this across ten or fifteen closed matters of the same type produces a range that reflects your practice specifically. That range is a far more defensible basis for an estimate than either an industry figure or an instinct.

Methodology and assumptions

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

  • Calendar days are the difference between the dates; business days exclude weekends. Months use an average month length of 30.44 days.
  • Hours per month and fees per month divide the totals by the elapsed months.
  • The effective rate divides fees billed by hours recorded.
  • 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

Should I use the open date or the date of first work?

Whichever you use consistently. The date of first substantive work is usually more meaningful than the file-opening date, which can precede it by weeks.

Why is the effective rate lower than my standard rate?

Because it uses fees billed rather than time recorded at standard rates. The difference is write-downs, discounts and any fixed-fee arrangement.

How many matters do I need before the range is useful?

Ten to fifteen of the same type is usually enough to see a pattern. Fewer than that and one unusual matter distorts the whole picture.

Does this predict how long a new matter will take?

No. It measures matters that have finished. Whether a new one resembles them is a judgement you make.

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