about 320 miles, 6 to 7 hour drive one way. I do it all the time.
this is from downtown SD to Flamingo road LV

i only drove it twice, and i generally don’t speed ever. it took me 9 hours, but i stopped a couple times too for gas and food, and there was some construction too somewhere after the Cajon Pass.

or you can find out yourself using mapquest. Just plug your starting point to your destination and go!

Depending on the traffic to/from Vegas and near San Diego, the trip will be at least four hours. On a bad day closer to eight. Best not hit either city during rush hour.

You can do it in 6 hours pending how fast you drive and if there is traffic.

approximately 6-7 hours