Why is it that when adding a Fuel up Fuelly calculates what you currently filled your tank up to vs how many miles you drove on your last fill up?
For example: on 9/14 I did my first fuel up but I always keep track of my tank to tank mileage so when it asked me what my last fuel up mileage was I input 411 and on that same date I put in 15.91 gallons of gas and automatically I received a 25.8MPG rating 411/15.91=25.8. What I don't get is I haven't even driven a mile in the 15.91 gallon fill up how does it calculate a MPG?
You are using tripometer tracking. So every time you enter a fuel-up at Fuelly you are telling Fuelly two things: 1.) How far you went from your last fuel-up. 2.) How much fuel it took to get back to full.
With those two pieces of information, Fuelly knows how much fuel you burned to go a specific distance. Fuelly isn't measuring the fuel you just put in the tank, it's letting you know how much fuel you burned since the last time your tank was full. Does that help?
ok this explains why my CX-5 and Altima's MPG wasn't matching up to fuelly. The car's MPG measures the current tank whereas Fuelly calculates last tanks miles driven divided by the gallons just filled up. I could always go back and edit old fuelups to how many miles I drove with that fill up? would that be more accurate you think?
That sounds like it'd be a hassle. You'd always be a fuel-up behind, and you'd have to keep your receipt until you fill up again—and then enter your last fuel-up instead of what you're currently filling.
You can use the site however it's best for you. But I'd go with easier over harder. You're more likely to keep up with it the less complicated it is.