For both your sake and mine, I prefer to charge per project/contract instead of per hour/day.
What a client pays me for are my skills and the end product itself, be it an online store or a business card, NOT how much time I spent on the project.
If I finish the project earlier than expected, that should be a bonus for the client since he gets what he wants done quicker. It’s not a bargaining chip to lower the contract price because I spent less time on it.
Likewise if I finish the project later than expected, it’s not a chance for me to ask for more money because I spent more time on it.
Just let your word ‘Yes’ mean yes, and your ‘No,’ no. —Matthew 5:37
My base rate for calculating the contract price is $50/hour. I calculate roughly how long it would take me to complete the project, allowing for hiccups along the road.
I don’t prefer charging per hour since I have wifely and motherly duties to care for as well. The client has no means of monitoring whether the hours they are paying me for will be solely devoted to the project or not. So to keep things fair for both parties, charging on a per project/contract basis and delivering by a set time-frame is the way to go.
For ongoing projects though, I recommend a monthly support subscription fee instead. (See below)
For ongoing projects, such as web hosting, ongoing updates, ongoing technical support, online store maintenance, etc., my rates range from $30-$150 per month depending on the work required.