Massallah pertaining to Qibla

Assalaamu Alaikum Wa Ramatullahi Wa Barakatuhu
I have recently used the website www.qiblalocator.com to determine qibla for my home. While doing so, I also checked the local musajids. Some appear to be a few degrees off. What is the “tolerance” (in degrees, if possible) off qibla for my salaah to be valid.