# Why do we round off gasoline purchases, even when paying by debit or credit? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [November 2, 2008, 3:39am UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673 "2008-11-02T03:39:42Z")\ **Posts on this page:** 13\ **Page:** 3
**Author:** ![Heffalump\_and\_Roo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heffalump_and_roo/32/7691_2.png) [@Heffalump\_and\_Roo](https://boards.straightdope.com/u/Heffalump_and_Roo)\ **Post date:** [November 3, 2008, 12:55am UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/41 "2008-11-03T00:55:25Z")
I don’t do it because I always read the sign on the gas pump that says that topping off is illegal, so I don’t. Were you talking about the royal “we” when you asked the question? Many more people here don’t round off here than do. ---
**Author:** ![phil417](https://avatars.discourse-cdn.com/v4/letter/p/6bbea6/32.png) [@phil417](https://boards.straightdope.com/u/phil417)\ **Post date:** [November 3, 2008, 6:09am UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/42 "2008-11-03T06:09:16Z")
I was taught to do that, back in the late '60’s to early '70’s…I was told it was to “top off the tank.” I still have no idea what that means. After all, if the sensor tells you the tank is full, how does adding a few more drops of gas “top it off”? The heck with that. Love, Phil ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [November 3, 2008, 9:01am UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/43 "2008-11-03T09:01:27Z")
If I have enough money to fill up I will. If I don’t I’ll often round, either to make it easier to mentally keep track of my bank account, or so that my account will still have multiples of $20 so I don’t get screwed when I try to use the ATM. ETA: Plus, pumping gas is boring. Trying to round it off adds a small amount of entertainment. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [November 3, 2008, 5:05pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/44 "2008-11-03T17:05:49Z")
> [@johnny l.a.](#): > > **chefguy** : The prius manual says the same thing. I haven’t read it in a while, but it says that overfilling can damage the fuel bladder. Like your honda, i don’t think it specifies what the damage is. **vindication!** ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [November 3, 2008, 5:50pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/45 "2008-11-03T17:50:32Z")
> [@Johnny\_L.A](#): > > 1. Battle of Hastings. It’s just one of those dates that’s always stuck in my head since I was a kid. You know, ‘This will be important for you to know when you grow up.’ Well, it hasn’t been. But it’s always stuck. And since the Jeep would take just about that much fuel every day… :shrug: You all should read [1066 and All That](http://en.wikipedia.org/wiki/1066_and_All_That) based on the observation that English history students only remember that date, pretty much. As for me, I rounded it when you paid cash, but I haven’t done it for years. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [November 3, 2008, 9:25pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/46 "2008-11-03T21:25:47Z")
> [@Heffalump\_and\_Roo](#): > > I don’t do it because I always read the sign on the gas pump that says that topping off is illegal, so I don’t. > > Were you talking about the royal “we” when you asked the question? Many more people here don’t round off here than do. Illegal? This just keeps getting more interesting. In what way is it illegal? And, no I originally wasn’t using the royal we. ---
**Author:** ![Agent\_Foxtrot](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@Agent\_Foxtrot](https://boards.straightdope.com/u/Agent_Foxtrot)\ **Post date:** [November 3, 2008, 9:27pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/47 "2008-11-03T21:27:34Z")
My wise ass generally tries to pump 2.718 or 3.142 gallons. I’d pump more, but I tend to buy small amounts of gas in hopes the prices will keep going down. ---
**Author:** ![Knorf](https://avatars.discourse-cdn.com/v4/letter/k/58956e/32.png) [@Knorf](https://boards.straightdope.com/u/Knorf)\ **Post date:** [November 3, 2008, 9:29pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/48 "2008-11-03T21:29:52Z")
I do not round it off, and haven’t for years. ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [November 3, 2008, 10:30pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/49 "2008-11-03T22:30:44Z")
> [@Leaffan](#): > > Illegal? This just keeps getting more interesting. In what way is it illegal? Rounding off isn’t illegal. But topping off is in some places. When the gas pump turns off you aren’t supposed to put any more gas in, for fear of it overflowing and creating a flammable hazard. ---
**Author:** ![Skald\_the\_Rhymer](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)\ **Post date:** [November 3, 2008, 10:36pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/50 "2008-11-03T22:36:23Z")
> [@What\_Exit](#): > > On the rare occasions I pump my gas, I just fill the tank. I never worry about rounding off as I am paying with a card. However, I am in Jersey and I have seen most pump jockeys fill the tank to even dollar amounts or at least to the .50. I cannot figure out why they bother. They’re making a game of it. Wouldn’t you be tempetd to? ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [November 3, 2008, 10:41pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/51 "2008-11-03T22:41:28Z")
> [@Mongo\_Ponton](#): > > I always stop at even dollar amounts simply because I never considered that it could be any other way. > > Hell, I’d fill the ashtrays if I needed to squeeze just that extra 3 cents. > > I always wondered why they didn’t have some sort of electronic detent for making it easier. When the prices went up so much it became harder to stop at exactly the right spot and you might have to go to the next 25 cent increment and ruin the whole rest of the day! > > What the hell’s the matter with you people? There has to be order in the world. Order in the world? Hell, don’t you know that if you fill the tank to an odd number of cents the universe itself will cease to exist! ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [November 3, 2008, 10:47pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/52 "2008-11-03T22:47:35Z")
> [@Leaffan](#): > > Yet I’m willing to bet we all do it, right? Nope. Not even a little. ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [November 3, 2008, 11:01pm UTC](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673/53 "2008-11-03T23:01:33Z")
I’ve never done it. I don’t pay cash for gas- I always use a credit card. I don’t keep a running total of my credit card expenditures- the card company is nice enough to send me one of those every month with the bill, so there’s no math that needs to be made easier. I don’t tend to have a problem with getting bored while at the gas pump. This may have something to do with the fact that the only cars I’ve ever owned were small (a Pontiac Sunfire and my current Honda Civic), and so don’t take a lot of time to fill up. [Previous page](https://boards.straightdope.com/t/why-do-we-round-off-gasoline-purchases-even-when-paying-by-debit-or-credit/470673.md?page=2)