Expert Witness Travel Billing — Half Rate, Full Rate, or Flat?

Published March 20, 2026 · 10 min read

Travel is one of the most contentious line items on an expert witness invoice. You blocked an entire day for a two-hour deposition three states away. The retaining attorney expects to pay your testimony rate for those two hours — and nothing else. You expect compensation for the ten hours of door-to-door travel that made the testimony possible. The dispute is predictable and preventable.

This guide covers the three models expert witnesses use to bill for travel time, how to handle expense reimbursement, and the engagement letter language that eliminates ambiguity before it becomes a dispute.

The Three Travel Billing Models

There is no single industry standard for travel time billing, which is precisely why it causes so many problems. Expert witnesses generally use one of three approaches, each with trade-offs.

Model 1: Half Rate (Most Common)

The majority of expert witnesses bill travel time at 50% of their standard hourly rate. This is the approach recommended by SEAK and reflected in most published fee surveys. The rationale is straightforward: travel requires your time and prevents you from doing other work, but it does not demand the same level of professional expertise as testimony or report writing.

If your standard consulting rate is $400/hour, you would bill travel at $200/hour. A full day of travel (8 hours) generates $1,600 — meaningful compensation without creating a billing entry that looks inflated on the invoice.

Half rate is the safest default. Courts are accustomed to seeing it, opposing counsel rarely challenges it, and retaining attorneys accept it as standard practice.

Model 2: Full Rate

Some experts charge their full hourly rate for travel, particularly when the travel itself displaces billable work. Surgeons who cancel clinic days, engineers who leave active project sites, and financial experts pulled from client engagements can justify full-rate travel because the opportunity cost is dollar-for-dollar.

Full-rate travel billing is defensible in specific circumstances but requires justification. If you charge $500/hour for travel and opposing counsel challenges the fee, you need to articulate why your travel time commands the same rate as your professional analysis.

When full rate is defensible: when you are reviewing case materials during transit (and you log that time as file review, not travel), when the travel displaces scheduled patient care or client work, or when your engagement letter explicitly states full-rate travel and the retaining attorney signed it without objection.

Model 3: Flat Fee

A growing number of experts use flat travel fees — a fixed amount per travel day regardless of distance or duration. Common structures include $1,500 per travel day, $2,000 for travel requiring an overnight stay, or tiered amounts based on distance (e.g., $750 for travel under 200 miles, $1,500 for 200-500 miles, $2,500 for travel over 500 miles).

Flat fees eliminate the need to track travel hours, simplify invoicing, and give the retaining attorney a predictable cost. The downside is inflexibility: a flat $1,500 fee overpays for a 90-minute drive and underpays for a full day of connections and layovers.

Comparing the Three Models

Portal-to-Portal vs. City-to-City

Whichever model you use, you need to define what counts as "travel time." The two conventions are portal-to-portal and city-to-city, and they can produce significantly different billable hours.

Portal-to-Portal

Portal-to-portal means door-to-door: the clock starts when you leave your home or office and stops when you arrive at the hotel or courthouse. This includes driving to the airport, waiting at the gate, flight time, layovers, ground transportation, and check-in. A trip that involves a 2.5-hour flight might generate 6-7 hours of billable travel under portal-to-portal.

Most experts use portal-to-portal because it reflects the actual time commitment. However, if you live 90 minutes from the nearest major airport, the drive to the airport alone adds three hours (round trip) that some attorneys will question.

City-to-City

City-to-city billing counts only the time from one metropolitan area to another — essentially the flight time plus reasonable ground transportation on each end. Your commute to the airport and wait time at the gate are excluded.

City-to-city is less favorable to the expert but may be appropriate when the retaining attorney is cost-sensitive or when you want to present a lean invoice. Some experts use city-to-city for air travel and portal-to-portal for driving.

The critical point: Whichever convention you use, state it explicitly in your engagement letter. Ambiguity here is the single most common cause of travel billing disputes.

Expense Reimbursement

Travel time billing is separate from expense reimbursement. Expenses are the actual costs incurred — airfare, hotel, rental car, meals — billed at cost and passed through to the retaining attorney. Your engagement letter should specify reimbursement terms for each category.

Airfare

Standard practice is coach/economy class for flights under four hours and business class for longer flights or red-eyes before testimony days. Some engagement letters cap airfare at "lowest available coach fare booked at least 14 days in advance" to prevent disputes over last-minute premium bookings. Keep confirmation emails and receipts for every flight.

Hotel

Reasonable hotel expenses are universally reimbursable. "Reasonable" generally means a mid-tier business hotel (Marriott, Hilton, Hyatt) rather than a luxury property. If the deposition or trial is in Manhattan or San Francisco, higher nightly rates are expected. Some experts cap their nightly rate in the engagement letter ($250/night, adjusted for high-cost cities) to set expectations.

Meals and Per Diem

You have two options: actual meal expenses with receipts, or a per diem based on IRS rates. The IRS per diem approach is cleaner — no need to save restaurant receipts, no debates about whether a $65 dinner was "reasonable." Current IRS per diem rates vary by city, ranging from $59 to $79 for meals and incidental expenses in most locations. High-cost cities like New York, D.C., and San Francisco have higher rates. You can find the current rates in IRS Publication 1542 or at GSA.gov.

Mileage

When driving to a deposition or trial, bill mileage at the current IRS standard mileage rate (67 cents per mile for 2025). This is a universally accepted reimbursement standard that no attorney will question. Include the origin, destination, and total miles on your invoice. For drives over 200 miles one-way, most experts fly instead — driving for six hours at half rate plus mileage often exceeds the cost of a flight.

Other Expenses

Rental cars, parking, tolls, and ground transportation (rideshare, taxi) are reimbursable at cost with receipts. Incidentals like airport Wi-Fi, baggage fees, and printing costs are typically included in the per diem or billed individually at cost. Do not bill for minibar charges, in-room movies, or personal items — it sounds obvious, but disputed expense reports have included all of these.

When to Charge Full Rate for Travel

There are situations where full-rate travel billing is both justified and expected:

• Same-day return trips for testimony: If you fly out at 6 AM for a 10 AM deposition and return on a 4 PM flight, you have lost the entire working day. Some experts bill the testimony hours at full rate and the remaining hours (travel + waiting) at their travel rate. Others bill the entire day at full rate with a daily minimum.
• Multi-day trial appearances: When you are required to be present in the courtroom for multiple days — whether or not you are on the stand — full-day billing at your testimony rate is standard. Travel days bookending the trial appearance are billed at your travel rate.
• Working during transit: If you are reviewing case materials, refining your report, or preparing for testimony during a flight, bill that time at your file review or trial preparation rate — not your travel rate. Log it separately with a description of the work performed. The travel entry covers only the non-working transit time.
• Last-minute travel: When an attorney requires you to travel on short notice (less than 72 hours), a premium is reasonable. Some engagement letters include a clause: "Travel arranged with less than 72 hours' notice will be billed at the full hourly rate."

Engagement Letter Language for Travel Terms

Your engagement letter should address travel billing with enough specificity to prevent disputes. Here is template language that covers the essentials:

Travel Time. Travel time shall be billed at 50% of my standard hourly rate, calculated portal-to-portal (from departure from my office or residence to arrival at the destination, and return). Travel time during which I am performing case-related work (document review, report preparation, testimony preparation) shall be billed at the applicable activity rate.

Travel Expenses. Reasonable travel expenses shall be reimbursed at cost, including: (a) airfare at coach/economy class for flights under 4 hours, business class for flights over 4 hours; (b) hotel at reasonable business-class rates; (c) meals at the applicable IRS per diem rate; (d) ground transportation (rental car, taxi, rideshare) at cost; (e) mileage at the current IRS standard mileage rate for personal vehicle use. Receipts will be provided for all expenses except per diem meals.

Travel Arrangements. Unless otherwise agreed, I will make my own travel arrangements. Travel booked with less than 72 hours' notice may be subject to premium fares, which will be billed at cost.

This language is specific enough to prevent disputes but flexible enough to cover most travel scenarios. Adjust the rate percentage, airfare class thresholds, and per diem approach to match your practice.

Travel Billing Disputes

Even with clear engagement letter terms, travel billing disputes arise. The most common challenges:

• "You billed 8 hours of travel for a 2-hour flight." This is a portal-to-portal vs. flight-time-only misunderstanding. Your engagement letter should define the measurement method. If it says portal-to-portal, point to the clause.
• "Business class was not authorized." If your engagement letter permits business class for flights over a certain duration, reference the clause. If it does not address airfare class, you have a weaker position — another reason to be specific in the engagement letter.
• "Your hotel was too expensive." Provide the receipt and demonstrate that the rate is consistent with mid-tier business hotels in that city. If your engagement letter caps the nightly rate, show compliance.
• "We should not pay for travel when the deposition was cancelled." If you had already traveled or purchased non-refundable tickets before the cancellation, those costs are sunk. Your engagement letter should include a cancellation clause covering non-refundable travel expenses.

Tracking Travel Time Alongside Case Work

The practical challenge of travel billing is tracking it correctly. Travel time needs to be logged as its own activity type at its own rate, separate from any case work performed during transit. If you reviewed documents for two hours on the plane and traveled for four hours total, you need two separate time entries: one for file review at your review rate, one for travel (net of working time) at your travel rate.

ExpertPractice includes Travel as a built-in activity type with its own rate in your per-case rate structure. Select the activity type, and the travel rate auto-fills — no mental math, no risk of accidentally billing travel at your testimony rate.