Range on a 2013 Prius 2

E: The tank is rated at 9.5 gals.

 

You'll never be able to use the rated capacity of the tank. Are you topping off to the top of the filler neck ?

 

welcome to priuschat harold! it's option B, the difference between what you pump, and the tank capacity rating is toyota's 'safety reserve'. you can drive another 50 -100 miles, but at some point, you're going to risk running out of fuel before you reach a gas station. your original plan of mpg times total fuel was using every drop and a bit unrealistic. all the best!

 

Don't run out of fuel, big problems

 

I've never been able to use the full fuel capacity in any vehicle I've owned, and didn't expect to. There's always a little fuel left in the tank even when the fuel pump starts sucking air. The worst example was the diesel truck I recently traded in. The theoretical capacity was 37 gallons, but that was split between 2 tanks. With 2-3 gallons unusable in each tank, that meant I had an actual capacity of about 32 gallons. This gave me about the same real range as my new Prius.

 

I vote for Option [B: Does the Prius have an ultraconservative fuel gauge/cruising range, leaving 2 full gallons in reserve (around 100 miles)]. But add the side comment that this is not ultraconservative, rather a normal industry practice to prevent angry driver complaints about running out of gas when the gauge still displayed fuel remaining, or going dry in unfavorable conditions on trips that the car successfully completed in other conditions. The driver is issued plenty of warning, so running dry isn't the car maker's fault.

For a typical fuel range, read the base post of this long thread: [WARNING] Running out of gas (Gen III). The real story of how the car quit is discovered deep in the thread, but the 'typical' numbers you want are in the OP. Beware that gauges vary among individual cars, and you could have drawn one of the short straws, so test it only when failure is not hazardous, not seriously inconvenient, and not terribly embarrassing.

I have intentionally run only one car (my last carbureted engine) out of gas, and it went about 120 miles past 'E'. Each subsequent car (including a 2010 Prius) has gone at least 40 miles past 'E' or the last warning, and refill volumes suggest each should have gone roughly 100 miles over. Last week I took my 2012 to 68 miles past DTE=0, or a bit over 90 miles past the flashing pip, and it took 11.2 gallons to the first click of the pump nozzle.

Not all cars have this generous fuel margin. The very first tank of the very first car I actually owned, accidentally ran dry with the gauge still slightly above 'E'. This happened shortly after my parents seriously teased me about being worried about running one of their cars below E, when they switched cars on me at the last minute before a special outing.

 

Be aware that if you are reading fuel economy off the screen, it could be up to 10% optimistic of what is actual.

My anecdotal survey of all cars I've ever owned is that the low fuel light comes on when there is about 2 gallons left in the tank regardless of the vehicle. I subtract the amount of fuel I fill up from rated capacity. On a 50 mpg Prius, it seems conservative. But on my 20 mpg Frontier, watch out, next gas station is 35 miles away. Perhaps the 2 gallons of fuel is to keep the fuel pump properly lubricated?

Anyway, I know exactly how you feel. I was filling up every 3 days with my 105 mile commute in my Civic. Then I started driving in the right lanes and got to 4 days every tank. But the only way I made 5 days was sweating on the last day as the low fuel light blinked. My PiP is now going on 7 days. I've driven up to 60 miles with the low fuel light blinking. It took barely 9 gallons. It's a wonderful feeling and I wonder if I can make it 2 full weeks.