Do you use more gas on a full tank or a half tank?

I hear from alot of people that you save more money on gas if you always fill your tank instead of filling it up every now and then. What do you think?

18 Answers

  • Anonymous
    1 decade ago
    Best Answer

    As for better fuel economy because there's less weight in the tank, it's hogwash. A car weighs a minimum 2000 pounds and the upside is unlimited, but let's say 6000 pounds. Now, a 20 gallon tank of gasoline weighs about 6 to 6.5 pounds per gallon, for a total weight of 120-130 pounds. This means a tank of fuel represents at most, 6.5% of a vehicle's gross weight and can be as low as 2.2%. This is for a full tank, mind you. It's about equal to saying when you have an additional friend in the car, you get worse gasoline mileage. Not very likely, is it?

    Keep in mind, a half tank is half of those numbers, and by weight, it's equal to a 3rd grader. I try to fill my tank whenever prices drop. This way, I'm saving money if it goes back up. If it goes down again, I simply fill up again. This way, I save as much money as possible. I don't worry about a few pounds for gasoline. I just can't be bothered pulling off the road to fill up only half my tank. I'd rather fill it and be done with it for as long as possible.

  • Olga
    Lv 4
    4 years ago

    Regardless of what you have for answers, physics plays into this game. Half full tank=1 fat in-law riding in the back seat Full tank=Both fat in-laws riding in the seat. So weight has everything to do with it. 1 gal=8 pounds or 80 for 10 gallons 20 gallon tank is160 lbs of dead weight 100 gallon tank and you can figure it out Etc So that is dead weight riding with you up them hills. You wanna toss 160 pounds on your shoulders and carry it up the mile long hill? Or 80 pounds? Remember in both cases you are running up the hill at the same speed. But the fact is you need some gas, so you are gonna have to carry somebody up. Many if not most people shoot off the line. If you are carrying 160 lbs it is not as fast as the dude who has the identical car and the identical take off time(the point of acceleration) so fatty loses. EXCEPT in snow. If you both got good winter tires and gas it about the same way "which is much more lighter so you do not spin" Fatty will have better traction than the lighter dude.. That is, if the gas tank is in the rear of the car. If your car is in good tune the variable is very little because it is a short distance. If you are shooting for the moon, the figuring it more tighter.

  • 4 years ago

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    Do you use more gas on a full tank or a half tank?

    I hear from alot of people that you save more money on gas if you always fill your tank instead of filling it up every now and then. What do you think?

    Source(s): gas full tank tank:
  • 1 decade ago

    I heard a full tank is better because there is less air in the tank that way, less air causes less evaporation of gas, especially when filling your tank. I don't think you would get better gas mileage with a full tank vs. half tank

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  • 1 decade ago

    Technically it should be the same, but from all the cars that I've had it always seems like the gas runs out much quicker once it's down half tank. This is mainly because the gauges are rarely accurate according to the shape and dimensions of the gas tank on a particular vehicle.

  • 1 decade ago

    It just seems that way because your fuel gauge goes past the full mark, so it makes you believe your getting more fuel from a full tank then a half a tank. weight has nothing to do with it

  • 1 decade ago

    I keep my tank full because I want to, not because I have some crazy ideas about saving money on gas. I don't really give a crap about the gas prices because they are not my fault. There is plenty of oil in America that we could access to lessen the strain on foreign supplies but apparently we are more concerned with the friggin trees, as usual.

  • 1 decade ago

    I drive a 97 neon and I can say that yes a half tank is better on fuel.

    It is like driving around with an extra person in the car when you are on full.

    I agree with all that gross weight stuff, but when you have a VERY small car, with a small engine, it adds up. Especially climbing hillls with the AC on and stuff...

  • 1 decade ago

    I can save more gas with a full tank of gas than i can with 1/2 tank of gas.... i have a 1985 chevy scottsdale with a 350 v8 and its horrible on gas...once it hits 1/2 tank the gas just starts to disappear fast

    Source(s): me
  • Scouse
    Lv 7
    1 decade ago

    Less on half a tank but I prefer to fill up when the tank gets below the quarter full

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