Freelance Interpreter Assignment Fee Calculator

Compute your full billable total — interpreting tiers, prep, travel pay, mileage, cancellation & surcharges

Assignment Details
Units & Currency
Interpreting Service
Your standard interpreting rate per hour
Actual time at the assignment (not incl. travel)
2 hrs on-site typical; 3–4 hrs remote; 1 hr medical
Preparation
Many interpreters bill prep at 50–100% of hourly
Travel
Time beyond this (each way) is billed. Commonly 0.5–1 hr.
50% is industry standard; some bill 25–100%
IRS 2026 rate: $0.725/mi · Use $0.28/km for metric
Overnight & Per Diem
Many agencies use $50–$75; federal CONUS rates vary by city
Surcharges
Late notice (<12-24 hrs): 10–25%; After-hours/weekend: 25–50%
Team Interpreter
Cancellation (if applicable)
Your Assignment Total
TOTAL BILLABLE —
Estimates for quoting & invoicing guidance. Verify rates and policies with your agency or client contract. Not professional legal or financial advice.

What is this calculator?

This tool computes the full billable total for a freelance interpreting assignment — not just interpreting hours, but every line item a professional invoice should include: minimum-hours enforcement, half-day and full-day tier upgrades, preparation and glossary time, billable travel time, IRS-rate mileage reimbursement, per diem, late-notice and after-hours surcharges, team interpreter fees, and cancellation amounts.

It replaces the multi-step mental arithmetic and spreadsheets that interpreters currently use to confirm their quote before sending an invoice or accepting an assignment.

How to use it

  1. Set your modality — on-site, VRI, or OPI. Travel fields appear only for on-site.
  2. Enter your rates — hourly, half-day (optional flat rate), full-day (optional flat rate), prep rate.
  3. Enter assignment hours — actual time at the assignment. The calculator applies minimum, half-day, or full-day tiers automatically.
  4. Fill in travel — actual one-way travel time, threshold, round-trip mileage, and parking/tolls.
  5. Add surcharges — a late-notice (e.g. 25%) or after-hours/weekend surcharge applies to the interpreting base only.
  6. Toggle team interpreter or cancellation if applicable.
  7. See your total update instantly. Print or copy to CSV for your invoice.

How the fee tiers work

Interpreting hours billed = MAX( actual hours , minimum hours )
↳ If billed ≥ half-day threshold → use half-day rate (or hourly × half-day hrs, whichever is higher)
↳ If billed ≥ full-day threshold → use full-day rate (or hourly × full-day hrs, whichever is higher)

Travel time billed = 2 × MAX(0, one-way travel − threshold) × (pay% / 100) × hourly
Mileage = round-trip miles × mileage rate
Prep = prep hours × (prep% / 100) × hourly
Per diem = nights × per diem rate
Surcharge = surcharge% × interpreting base fee
Team interpreter fee = team hours × team hourly rate
Cancellation fee = cancellation hours × hourly rate

The surcharge applies only to the interpreting service fee, not to travel, mileage, or per diem — consistent with standard industry practice.

Industry standards & sources

Minimum hours

A 2-hour minimum is standard for on-site interpreting — even a short appointment ties up the interpreter's schedule. Healthcare settings commonly use 1-hour minimums; legal and conference settings often require 2–4 hours. Source: NAJIT (National Association of Judiciary Interpreters & Translators) and RID (Registry of Interpreters for the Deaf) guidelines.

Half-day & full-day tiers

The industry norm is 3.5 hours for a half-day and 7 hours for a full day (consistent with Pennsylvania court interpreter fee schedules and common conference interpreting contracts). Some agencies use 4 hours / 8 hours. Enter your own thresholds.

Travel time pay

Travel time exceeding a threshold (commonly 30–60 minutes one way) is typically billed at 50% of the hourly interpreting rate for the excess round-trip time. Some interpreters bill at 25–100%. Source: NAJIT guidelines and sample interpreter contracts.

Mileage

The 2026 IRS standard business mileage rate is $0.725 per mile (IRS Notice 2026-10, effective January 1, 2026), up from $0.70 in 2025. This is the benchmark rate used by most interpreting agencies. For metric users, the approximate equivalent is ~$0.45/km ($0.725 ÷ 1.609). Parking and tolls are reimbursed at cost and are separate from the mileage rate.

Cancellation fees

Cancellation within 24–48 business hours typically triggers a fee equal to the minimum billable hours at the interpreter's rate. On-site no-shows are usually billed at the full contracted time. Multi-day assignments may follow a tiered formula (full first day + 2 hours per additional cancelled day).

Worked example

Scenario: A freelance ASL interpreter accepts a 2.5-hour medical deposition, 45 minutes one-way by car. Hourly rate $90, minimum 2 hours, half-day at 3.5 hours, full-day at 7 hours. 1 hour of prep at 50%. Round-trip 40 miles at IRS rate. Assignment was called with 10 hours' notice (late-notice surcharge 25%). No cancellation.

  • Interpreting fee: 2.5 hrs ≥ 2 hr min → billed 2.5 hrs × $90 = $225.00
  • Late-notice surcharge (25% on $225): $56.25
  • Prep fee: 1 hr × 50% × $90 = $45.00
  • Travel time: one-way 0.75 hr − 0.5 hr threshold = 0.25 hr excess × 2 (round trip) × 50% × $90 = $22.50
  • Mileage: 40 mi × $0.725 = $29.00
  • Total: $377.75

Frequently asked questions

How do freelance interpreters calculate their assignment fee?
Freelance interpreters start with a base interpreting fee that applies a minimum-hour floor and steps up to half-day or full-day flat rates at set thresholds. To that base they add preparation time (often 50–100% of hourly), billable travel time (typically 50% of hourly for time beyond a threshold, round-trip), mileage at the IRS rate, per diem for overnight travel, and any late-notice or after-hours surcharges. A second team interpreter's fee is added separately if applicable.
What is the standard minimum booking time for interpreters?
Most freelance interpreters require a 2-hour minimum for on-site assignments — a 20-minute appointment still takes the same setup and travel. Healthcare settings sometimes use 1-hour minimums. Legal and conference settings often require 2–4 hours. Remote OPI/VRI interpreting typically uses per-minute billing with a 30-minute minimum. The minimum ensures the interpreter is compensated for opportunity cost — blocking the slot means forgoing other bookings.
How is a cancellation fee calculated for interpreters?
Cancellation fees typically equal the minimum billable hours at the interpreter's rate when the cancellation comes with less than 24–48 business hours' notice. If the interpreter arrives on-site and the event is cancelled or the client is a no-show, the full contracted time is usually billed. For multi-day assignments, some courts and agencies charge one full day for the first cancelled day plus 2 hours for each additional cancelled day. This tool calculates that amount separately so you can quote it in advance.
Do interpreters charge for travel time?
Yes, for on-site assignments. The industry norm is to bill travel time that exceeds a threshold (commonly 30–60 minutes one way) at 50% of the hourly interpreting rate for the excess round-trip travel time. Mileage is billed separately at the IRS standard rate — $0.725/mile for 2026. Parking and tolls are passed through at cost. Remote (VRI/OPI) interpreting does not typically include travel pay.
When is a second (team) interpreter required?
Professional guidelines from RID recommend a two-interpreter team for any assignment exceeding 1–2 hours of continuous interpreting. High-demand settings — legal proceedings, large conferences, platform interpreting with significant audience participation, or Deaf-Blind assignments — typically require a team regardless of duration. When you supply both interpreters, the second interpreter's full fee is added to the invoice. Team-interpreter surcharges of 20–50% on the primary fee are common when you are coordinating through an agency.
What is the 2026 IRS standard mileage rate for interpreters?
The 2026 IRS standard business mileage rate is 72.5 cents per mile ($0.725), effective January 1, 2026, as set by IRS Notice 2026-10. This is the benchmark most interpreters and agencies use for mileage reimbursement. The 2025 rate was 70 cents per mile. The rate applies to all vehicle types including electric and hybrid. Note that parking and tolls are not included in the mileage rate and should be listed as separate invoice line items.
Should remote (VRI/OPI) interpreting be billed differently?
Yes. Remote interpreting typically has no travel pay or mileage, but may carry higher minimum bookings (3–4 hours) and sometimes a slightly higher hourly rate to compensate for increased cognitive load — research shows remote interpreting causes faster fatigue than in-person work. Per-minute billing with a 30-minute minimum is also common for OPI. This calculator hides the travel section when VRI or OPI is selected.