The short answer: You should bill each consultant out at 1/1000th (0.1%) of their annual salary.

First of all, congratulations on doing this as an hourly cost with a fixed number of hours. That makes your life infinitely better than if you had to do it for a fixed price and were spending the rest of your life arguing over what's INCLUDED in the fixed price!

Back to your question...

For consulting jobs like this, you usually see a range of different hourly prices.

At the LOW end of the range, you have individual, independent consultants. They usually charge 1/1000th of an annual salary. Why?

1. There are about 2000 hours in a normal working year. (52 weeks - 2 weeks vacation * 40 hours a week). Very rough estimate.

2. However, as an independent consultant, you supply your own equipment, you pay for your own benefits, vacation, sick days, health insurance, regular insurance, and employment taxes (depending on country, of course).

3. Also, an independent consultant must spend a lot of time finding clients.

4. And the client has a lot more flexibility with independent consultants compared to full time employees, ESPECIALLY in Europe where firing full time employees can be a challenge

So all this adds up to = the right rate for an independent consultant is 1/1000th of the annual salary that person would be getting for the same job.

That is the LOW END price for hourly work like this.

The HIGH END is what large, prestigious consulting firms might charge: Microsoft Consulting, IBM, the big accounting firms, etc. That will be as much as four times higher, i.e. 1/250th of an annual salary. What's the logic of this? Well, nothing really:

1. They have to pay for a lot of fancy glass and steel skyscrapers in every city, filled with secretaries, assistant mail delivery boys, marketing, public relations, etc.

2. They have to pay for partners, who need to take home at least $1,000,000 a year in exchange for playing golf with two or three clients every month.

3. They can get away with it, because the stupider companies are too scared to hire small firms.

Where are you on the scale from 1/1000th of a salary to 1/250th of a salary? I would argue that as a new company, you're a lot closer to the 1/1000th position... you're not THAT different than an independent consultant. So that's where I would start. Once you have more experience, more clients, and more demand for your services, you can gradually try to raise prices... for example, a good rule of thumb is, if you find that you have more than 3 months of bookings already made, you should probably start raising your rates until people start turning you down.