I will paraphrase what is taught by Bilal Philips at IOU since I do not remember the exact wording (maybe someone else can precisely quote the hadith for me, insha'Allah?):
The Prophet (pbuh) was traveling to the north of Mecca with some of his companions, and one of them asked about the direction of the Kabbah for the purpose of prayer, I believe was the situation. And the Prophet (pbuh) said, pointing toward the south, that everything from the East to the West is the direction of the Kabbah.
So, a range of 180 degrees. If you know the
general direction of the Kabbah - if you are in the US it is in the east, actually it's more to the northeast because of the way rhumb lines work - and pray in that direction, your prayer will be accepted.
If you wish to be more precise, there are several qibla compass applications you can download for your phone, or an actual qibla compass is around $4-5 dollars. This site
https://www.halaltrip.com/prayertimes/qibla-direction/ will also show you the correct direction.