Your best answer will come from your zoning/building department. It depends on the size of the window, heated or unheated and you city, state requirements.

Wendy Rocca
Century 21 Commonwealth
617-383-8330

Here is my suggestion, do not count in the total bedroom count that bedroom, but mention it in the description of the property so that any potential buyer will know that there may be another bedroom or spare room....
Hope this helps..
Edith karoline YourRealtor4Life!
Working always in the very BEST interest of her clients....
EdithSellsHomes@gmail.lcom

Good answers but I would like to add another comment. In my market we usually check with the building department to find out if the space had proper permits. Also, if the property has a septic system it would need to be upgraded for the extra bedroom.

Hello, I used to live in Joneboro, GA. In most areas a basement is considered Below Grade GLA (Gross Living Area). To count as a bedroom it needs a window large enough for a fire escape and a closet. Check with your Building Code Department in your City or County for the size of the window they require. Also is there any entrance to a Garage or Outside Exterior this also would have a to have a reinforced Door with Safety Springs. How do you get to this Bedroom from a Hallway or from another room. You can't enter a Bedroom from another room and meet FHA/VA requirements. Bedrooms must come from a Hallway with a door that closes. It may be a Hollow Core Door from a Hallway. Your Local Building Department would have this answer too.

If it has a door then, YES.

It seems like it meets most requirements for a bedroom. However, every state is different. In some states bedrooms below grade (basements) can not advertise a bedroom in the basement or count it in the room count.

sorry, i didn't address room in the basement. if it meets the requirements of a bedroom i mentioned below, you could advertise the house as a 4BR "plus bonus"...

Typically, a room can be counted as a bedroom if it has 2 exits. This is for safety reasons. A door into the rest of the house and a window would satisfy this. So yes you could call it a bedroom.