I have been doing residential cleaning and charge by the hour. I now have the opportunity to bid on a cleaning job for a dental office. I have no idea how to charge! Help please

You estimate how many hours it will take you to empty garbage cans, vacuum and mop, dust surfaces. You should have a rough idea from what you normally clean. This is no different and probably a step up for you to make more money. Do a walk-about there and take a good look around, you will figure it out. Of course, now you are into the big time and will have to invoice, charge taxes, etc. You will probably need to apply for a business licence if you don't already have one. You should look into that aspect.

I agree with figuring out how many hours it might take you to do the job and figuring your bid based on that. Whether you will need a license for this, you would need to be contacting the city officials where you will be doing the work. For labor, it would depend on the tax laws where you are working as to whether you would charge taxes.