A question that has been answered many times. I am assuming you are talking about the range reported on your dash. The Guess-O-Meter (GOM) is what gives you an Estimate on your range. It bases itself on recent driving history. If you drive around town at slow speeds, regenerating a lot, the GOM will give you a high range. I have seen super high numbers. If you drive in winter, uphill, headwind and at 80 mph, your GOM may give you 250 or less range. It is just an estimate and should never be used as your actual "Range".
A better estimate is to look at the number on your dash of miles per kilowatts. This gives you a much more accurate at your power consumption. If you are recording 6.0 miles per kilowatt, you are heading towards 300+ miles of range. If you have the heater full blast and it reads 2.5 miles per kilowatt, you are down around 250 miles of range. Keep you head in your energy consumption and you will be able to measure your range better. Plan ahead for trips with weather and elevation change in mind. You'll have a much more relaxed trip.