It varies of course depending upon the orbit of the planet. At it's closest Earth is approximately 91.5 million miles from the sun, at the farthest about 94.5 million. Taking an average distance gives you about 93 million miles. That given you can do the appropriate math, which will come out somewhere around 8 minutes give or take.
About eight minutes is "close enough for government work," but if you REALLY want to KNOW, the relevant facts are that the speed of light is almost exactly 186,000 miles per second, and the average distance of the earth from the sun--longer axis slightly more, shorter axis slightly less--is 93,000,000 miles. Simple arithmetic tells us that the travel time of light from the sun to the earth is therefore 500 sec., give or take a little, depending on the precise position of Earth on its orbital path--500 seconds working out to 8 min. 20 sec., + or - that little bit.