3-5K. Anywhere in there is fine. Just hold it steady and check the voltage at the battery. Compare to the dash gauge to get an idea how far off it is. I'd bet your gauge is a full volt off. Like John said, the gauge is more to show trends than exact measurements. I put a cigarette lighter DVM in my fairing pocket to give me a much more accurate check.
A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed.