The contacts prescription is different from glasses prescription. However, the difference is negligable unless the prescription is stronger than -4.00. So if you don't have a stronger prescription than -4.00,your contact prescription would be the same strength as your glasses prescription. On the contrary, your contacts prescription is lower than glasses prescription because the contacts sit directly on the eyeball while glasses are away from eyes.
No, the contacts prescription are usually lower than glasses cuz they are worn directly on the eyes. When you are getting contacts, you are required to have an eye exam and take the prescription for contacts.