Hong Life CalculatorsUnderstanding the consulting fee calculator — concept and principle
Consultants, coaches, lawyers, designers and other advisers are often paid by the hour, but the hour in the meeting is not the only hour of work. Preparing beforehand, writing notes and following up afterwards all take time. This calculator adds preparation time to the meeting hours, multiplies by your hourly rate and adds expenses, so you can quote a total fee that pays for all the work. It works with any currency.
How it is calculated
Billable hours = meeting hours × (1 + preparation ratio)
Total fee = billable hours × hourly rate + expenses
- Hours: client-facing or core working hours (meetings, workshops, calls).
- Hourly rate: what you charge per hour of work.
- Preparation ratio: preparation and follow-up hours per meeting hour. 0.5 means 30 minutes of prep for every hour in the room.
- Expenses: travel, materials or other costs passed through to the client.
The principle
If you charge only for visible hours, preparation becomes unpaid work and your real hourly income falls. With a 0.5 prep ratio and billing only meeting time, you would actually earn 1 ÷ 1.5 ≈ 67% of your stated rate. Building the ratio into the quote turns hidden time into billed time. Expenses are added separately because they are reimbursements, not income for your time.
Worked example
- Billable hours: 20 × (1 + 0.5) = 30 hours.
- Fee for time: 30 × $150 = $4,500.
- Add expenses: $4,500 + $0 = $4,500.00 total fee.
How to read the result
The total fee is the price that pays you your full rate for every hour you actually work. The billable-hours figure is useful when you present the quote: showing 20 meeting hours plus 10 preparation hours explains the price better than a single number. Track your real prep ratio over a few projects; new topics often need a ratio of 1 or more, while repeated workshops may need far less. To check your rate, compare annual income with the number of hours you can realistically bill in a year, not with 40 hours a week.
Common mistakes
- Quoting only meeting hours and absorbing preparation, travel and reporting time.
- Using an hourly rate copied from employment salary, which ignores unpaid admin time, holidays and overheads.
- Adding expenses with a margin without telling the client, which can damage trust.
- Forgetting sales tax or VAT where it applies.
Frequently asked questions
What preparation ratio is typical?
There is no standard figure. Measure your own time for a few engagements; complex or new work often needs more preparation than delivery time.
Should I charge a project fee instead of hourly?
A fixed fee rewards efficiency and gives the client certainty. You can still use this calculator to estimate the hours behind a fixed price.
Do I bill travel time?
Policies vary. Many advisers bill travel at a reduced rate or include it in a day rate; agree it in writing before the work starts.
Sources: Maister, D. H., Managing the Professional Service Firm (Free Press) · Weiss, A., Million Dollar Consulting (McGraw-Hill)