The average per hour rates for babysitters vary according to your location, like in some US cities, the minimum hourly rate can be as high as $16.75, while in some others, it can be as low as $11.25.
This rate also depends upon the number of children you are sitting, special occasions, special needs of the children, added housework, and your expertise in the job.
Do some research on the average babysitting rate in your city, consider the circumstances, and charge your employers accordingly.