What Is "Tare," And How Does It Impact Everything In The Supermarket?

“Tare” or “tare weight” is the weight of an empty container. Tare is not included in a goods’ net weight. So, for instance, 32-oz jar of mayo on the supermarket shelf should actually weight more than two pounds.

A group of 4th graders in Arizona learned this as part of National Weights and Measures Week (save the date: March 5-9), and now you do too. — BEN POPKEN

ADWM Alert June 2007 (PDF) [Arizona Department of Weights & Measures]
Tare Weight [Wikipedia]


Edit Your Comment

  1. The Walking Eye says:

    Now I can go and win on “Are You Smarter Than a 5th Grader.” Thanks Ben!

  2. levenhopper says:

    the link to the PDF is dead :(

  3. darkfyre says:

    Yeah, I used to work at a Whole Foods, and tare weight is configurable by the cashier. So all the cashiers could hook eachother up by entering an artificially high tare code, thus reducing the weight of the food being weighed and sold. I’m not really sure what this knowledge will do for anyone who doesn’t work in a grocery store, but I think it’s cool that consumerist wants you to know how it all works.

  4. Ben Popken says:

    @levenhopper: Fixed.

  5. jrlcopy says:

    Tare also impacts your grocery store visits in the produce section, as a recent cashier through high school, all registers are equipped with this magical button, and anytime we had a produce item that was weighable, we were ‘supposed’ to hit that tare button so that it took off those couple pennies.

  6. levenhopper says:

    thanks ben!

  7. levenhopper says:

    Thanks Ben!

  8. homersays says:

    All jewelery scales have a tare button. I think all scales should have one, it is a nice feature.

  9. MariSama44 says:

    Tare is soooo high school chemistry class. I remember how it haunted me when I was measuring chemical compounds.

  10. Jigen says:

    We had a lady a couple months back threaten to go to the District Attorney on us, due to her not understanding the concept of tare.
    She was yelling at a co-worker of mine about how the price was more when you weight produce in a bag. Tried to explain to her how the scale starts off at -.01 (which is actually displayed on the scales screen) thus negating the weight of the bag, but she just kept yelling.
    Told us she was going to go to the DA and get us in legal trouble for stealing money from customers. Told her to knock herself out cause we aren’t and that in fact shes stealing from us by not weighing her produce in a bag.

  11. legerdemain says:

    Whoo – I’ve got a case of Baader-Meinhof here. Just this morning, I thought to myself that “tare” was one of those words whose meaning I don’t know, but that I never seem to get around to looking up. Thanks Consumerist.

  12. karmaghost says:

    The grocery store I work at has many different tares, as I’m sure most others do as well. We have a “Wokery” bar (which is P.C. for “Chinese food”) and each container has it’s own tare code. A container with a tare of 3 is smaller than one with a tare of 5. The tare button must be pushed or the register won’t weight the item, this way customers aren’t over charged (unless, of course, the cashier puts in a lower tare on a higher tared container). I’ve had instances where customers have gone to the Wokery and grabbed one little piece of something and plopped it in a big container; when it was weighed, the computer would yell at us and say there wasn’t anything on the scale.

    Briefly: each state has it’s own Weights and Measures that comes by regularly (usually once a month) to officially check each scale in the store. If anything’s off, we have to send it out to get fixed and they need to recheck it before it can be used again. They’re very strict about that stuff.

  13. Every drug dealer worth his salt could have told you this. Weigh the baggie, press the tare button, THEN add the product.

    Duh. ;)

  14. Snakeophelia says:

    I’m trying to decide if I would have found a field trip to the local grocery store exciting when I was a kid. I don’t think so. Knowing a word and concept that my older sister probably didn’t know, and taunting her about it the next time we visited the supermarket – THAT, I would have found exciting.

  15. levenhopper says:

    @Jigen: and of course, the DA would take up a case involving maybe 2 cents, at most…

  16. DeeJayQueue says:

    It’s great that we know what Tare is and what it means. It’s also great that we know how that applies to food bought at the produce section or at the salad bar or the buffet. What I want to know is how that affects regular food. Like Ben said, the weight of the mayo shouldn’t include the jar, so what if it does? How to we rectify that? If a company started selling things by the gross weight instead of the net weight would we even know the difference? (Yes I know the label says Net Wt on it, but we all know that labels lie, don’t we.) If we found a problem what would we do to fix it? At least if your tomatoes aren’t getting weighed right you can bitch and moan to the manager and they have the power to fix it right there, but you can’t complain that your mayo doesn’t weigh enough.

  17. Jurph says:

    Turns out the state is already involved and the D.A. would laugh this lady out of his office. Any scale used to conduct business should have a seal on it from your state’s department of commerce*, certifying that within the last (30/60/90/etc) days it was weighing zero as zero, and measuring faithfully up through its maximum weight. You’ll also see these seals on gasoline pumps and at FedEx counters, and wherever products are priced according to their measure on store-owned equipment.

    * – or Bureau of Weights and Measures, or Agriculture and Labor Department…

  18. Nytmare says:

    How much tare are those wispy-thin clear plastic baggies you put tomatoes in? I guess I always assumed their weight was negligible.

  19. erica.blog says:

    @homersays: I think all scales should have one, it is a nice feature.

    Most scales do, except for home bathroom scales. It lets you factor out the weight of an empty container, and also lets you compensate for any drift over time (or dust/grease on the scale top, etc).

    It would be nice to have it on bathroom scales, and be able to knock a few pounds off for a towel or clothing… although I suspect it would quickly get abused by dieters — “Well, my shoes are, hmmm… 5 pounds… it’s winter, that heavy sweater must be a good 5 pounds… oh yeah, I shouldn’t count my hair as body mass, that’s a good 5 pounds too…” :-)

  20. nffcnnr says:

    i thought the 32 oz. on the jars of mayonniase and other products was the volume, not the weight. hmmm…

  21. swalve says:

    deejayqueue- Which labels lie?

  22. synergy says:

    @erica.blog: lol that’s why you weigh yourself on the way in or out of the shower. ;)

  23. swalve says:

    Usually the label says “net wt.” [weight] or “12 fl oz” [fluid ounces] to tell you whether it’s liquid or weight measure.

  24. synergy says:

    Honestly, did they have to waste the kids’ time to haul them to a grocery store just so they could learn about scales. I hope they taught them something else useful in there like proper nutrition and reading the labels. And price-comparison. O_o

  25. @nytmare: I have reuseable cloth produce bags of a very fine, light cloth, and even THOSE are so light the supermarket checkout scale typically doesn’t register them; the plastic bags are much lighter even than that.

    If you go during a quiet period, they’ll probably let you test it on a U-Scan if you ask nicely. I was curious as to how much my cloth bags would add to my bill.

    Although honestly, if every now and then a fraction of an ounce from the bag (either plastic or my own) costs me an extra penny, I’m not really that upset about it. It’s not like the supermarket keeps it a big secret that they weigh things in the bag, and I’m willing to accept an extra penny here and there as the price of the bag, or the cost of the convenience of the supermarket.

    (I’d be even happier if they’d knock off the nickle for bringing your own bags like a lot of chains do, but oh well.)

  26. esquilax says:

    it’s National Weights and Measures Week and i have not a thing to wear!

  27. adamondi says:

    @nffcnnr: Right you are. I was wondering why Mayonnaise was used as an example for Tare weight. Mayo, ketchup, mustard, tartar sauce, etc. These are all labeled in fluid ounces and are done by volume rather than weight.

  28. pearlandopal says:

    @Eyebrows McGee: Where did you get your cloth produce bags? How much of a pain are they to maintain?