Professional painters normally charge by the job for interior painting. Costs for painting vary depending on the experience of the painter, how much preparation work is needed, how many people are painting, where you are located, and the quality of supplies you want to use.
Prices vary widely for interior painting, so get several bids before choosing a painter. Generally, a bid for the entire job is better for both the customer and the painter, since the speed of painting varies between painters. What one painter considers to be a 10 hour job might be a 20 hour job for another painter, so basing the estimate on the cost per hour would not be wise. A simple room without complex trim work usually costs £130 - £195.
When requesting a cost estimate, clarify specifically the exact tasks the painter should provide to complete the job. For example, do you expect him to paint baseboards and trim, doors, or the interior of closets and cupboards? The painter may charge extra for each of these items, so make sure these and any additional items are included in the cost estimate.
Set aside a day to have several painters visit and look at the job so they can each provide an accurate estimate of the cost. Ask each painter to submit a written bid of their estimate. You should expect a bid from each within 48 hours.