Here is a formula that I have arrived by using my experience and the experience of many other people who estimate work.
This formula was not derived for just woodworking, but just in general.

((first guess of time X 3) + 15%) + materials = cost

Or for those who took some sort of engineering use PI (3.14)

Remember use the first estimate of how long you think it wll take. The multiplier of 3 is how long it will probably take
and then the 15% is for unknowns.

JAW


William wrote:
I got a prospective client who would like their maple lobby desk refinished.
I'm not really sure what to charge.

The job involves refinishing the top surfaces of a maple lobby desk
that has been worn from use. Approximately 30 sq feet of flat surface.
Additionally the front entrance side is another 20 square feet of maple
veneer. The customer wants this re-stained to match the existing finish
and a satin protective finish. As a final touch the customer would like to
have a brass kick plate installed at the base.
this would probably be 3/16x4x12feet long.
Any pricing guidelines I should follow? any help on what price range I
should charge?