Net Contents – Weight and Volume

All products sold to consumers, including soap and cosmetics, require the net contents to be placed on the label. In this post, we’re going to discuss how you measure the net contents and how it should be worded on the product label.

There are two different ways to measure products for sale – by volume and by weight.

Measuring by Volume

When a product is liquid (or at least pourable) it should be measured by volume. Products to be measured by volume include, for example, sprays, lotions, and perfume.

The units used for liquid products are by volume – how much space the product fills up. Volume measurements include:

  • fluid ounce
  • teaspoon
  • tablespoon
  • cup
  • pint
  • quart
  • milliliter
  • liter
  • cubic centimeter

While all these are valid volume measurements, the only ones that should be used on a label are fluid ounce (fl oz) and milliliter (ml).

Most containers – jars, bottles, tubes, etc – are sold based on their volume, such as a 2 oz jar or an 8 oz bottle. In that case, the jar or bottle will hold that many fluid ounces.

On the Label

On the label, the contents should be stated as __ fl oz ( __ ml).  For example: 4 fl oz (118 ml).  Place it on the front of the container, in the bottom 1/3 of the label.

There are 29.5735 ml in one fluid ounce.  When calculating the number of ml, don’t use decimal places; round down to the next whole number.

Measuring by Weight

When a product is solid or semi-solid, it should be measured by weight. Products to be measured by weight could include, for example, soap, massage oil, cream, whipped body butter or bath bombs. Weight measurements include:

  • avoirdupois ounce (that’s an ounce by weight)
  • pound
  • gram
  • kilogram

The correct measurements for a product label are only ounce (oz) and gram (g).

The oddity of ounces

While ounces by volume and ounces by weight are both called “ounces,” they only work out to be identical when measuring water. For water, 1 fluid ounce actually weighs one avoirdupois ounce; one cup (8 fluid ounces) of water really does weigh 8 ounces.  But there it ends.

Most things weigh more or less than water – they sink or they float. Consider whipped egg whites: 2 cups of egg whites (16 oz by volume) doesn’t weigh as much as a pound of butter (16 oz by weight). When it comes to soap and cosmetics, some products weigh more ounces (by weight) than the number of ounces by volume. For example, an 8 oz jar (by volume) will normally hold 10 – 12 ounces (by weight) of salt or sugar scrub,  but only 4 – 6 ounces of whipped body butter.

For solid or semi-solid products, it is important to actually weigh the amount of product that will fit in the container and put that amount in the net contents. You may be surprised!

On the Label

On the label, the contents should be stated as “Net weight __ oz ( __ g)”. You can also use “wt” instead of “weight”. For example: Net Weight 4 oz (113 g). Note that the words “Net Weight” or “net wt” are required on products labeled by weight. Place it on the front of the container, in the bottom 1/3 of the label.

There are 28.3495 grams in one avoirdupois ounce. When calculating, don’t use decimals; round down to the next whole number.

Why is it Important?

One of the most inspected, checked and important pieces of information on the label is the statement of the net contents. It tells the consumer how much of the product they are going to get.

By correctly stating the net contents you are correctly informing the consumer and they can make an educated decision about the value of the product.

Incorrectly stating the net contents not only could upset the consumer, it could also be considered “false and misleading” — something that government agencies and inspectors don’t like very much at all.

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30 responses to “Net Contents – Weight and Volume”

  1. Lena

    Hi Marie Gale, thank you for the article.
    I have a question: a mistake has crept into a print file and I need to know whether it still can be sold in the US:
    It mentiond Net X oz.
    The Wt. has been ommitted by mistake.

    1. Marie Gale

      I can’t say how the FDA might react in this case. I can say that I’ve never seen a recall order for something like this; it would be most likely that you’d be warned and told to correct it.

  2. Nice content. Very informative! I agree that net contents need to be correct in labeling.

  3. Hey! not sure if this is posted or emailed, but i am wondering if i can ask a few questions about calculating oils for a product

    1. Marie Gale

      If it’s a simple question, you can email me If you want to go into some depth, I offer hourly consulting. Note, though, that my area of expertise is regarding the labeling and calculating the net weight, not on determining which are the best oils for a formulation.

  4. Shenen

    I’m filling a 30mL bottle with a liquid. However, the manufacture is using a fill average of 28.5 +/- 1.5 mL due to margin of error while filling. Can I use 1oz/30mL (which is the intended fill level) or do I need to claim 0.9oz/27mL?

    1. Marie Gale

      Actually, 1 ounce is 29.57 ml. You shouldn’t claim 1 oz unless there is at least 1 ounce actually in the container. Don’t claim more than is actually there. If some of the bottles are 27 mL, you should use that.

      1. Shenen

        Thank you for the clarification on this. I was just wondering due to the labeling requirements including the “estimated” symbol.

  5. Ebonee Bethea

    How do I measure fl oz and ml for oils and liquids? Is there a conversion chart? I’m confused how to measure and label containers for oils and shampoos. A regular scale oz won’t work, correct?

    1. Marie Gale

      There are two different points to be addressed here:

      First, FORMULATION. This is your recipe and measuring ingredients to go into your product. Best practice is that all ingredients are measured by weight, regardless of whether they are liquid or solid. Ideally, your formulation should have everything by weight. If you have everything by weight it is much easier to make your ingredient declaration.

      If your recipe isn’t by weight now, you can convert it by measuring out the fluid ingredients you have by volume (teaspoon, tablespoon, fluid ounce, cup, etc) and then weighing that amount of that ingredient, and put that WEIGHT into your fomulation.

      Second, NET CONTENTS STATEMENT. The net contents statement for fluid products should be by volume (fluid ounces and milliliters). After you make the product and are filling your container, you need to measure the amount of fluid product by fluid ounces, and use that on the net content statement. If you are filling an 8 oz bottle, then your fluid ounces should be stated as “8 oz (236 ml)”.

      You can check the volume of your container by using the weight of WATER. (28.35 g of water = 1 fluid ounce). Weigh out 28.35 X # oz of water (i.e., to cacluclate 8 fluid ounces then 28.35 x 8 = 226.8 grams) of water. Pour that into the container. That’s the fill line for 8 FLUID ounces. Fill the container with that amount of liquid product (regardless of how much the PRODUCT weighs).

  6. Sarah Davis

    I’m so confused. I make a whipped tallow balm and use 2oz and 4 oz tins. I usually fill them full and put 2 oz and 4 oz on my labels because it fills my tins to that size. Do I also need to put weight? The whipped tallow balm is very fluffy and light can can possible be squeezed if I were to put it in a squeeze bottle. I hope you can clarify this! Thank you!

    1. Marie Gale

      A whipped balm is usually considered “solid” or “semi-solid” so the net contents should be by WEIGHT (ounces and grams). The tins are 2 or 4 ounces by VOLUME (like a measuring cup). 1 cup (8 ounces) of WATER by volume will WEIGH 8 ounces by weight—but ONLY water. Anything else weighs more or less than water. Oil and air weigh less than water, so 2 ounces of your balm (made with oils and having been whipped up with air), will be 2 ounces by volume, but it will weigh much less than 2 ounces by weight.

      What fills a 2 ounce tin will probably WEIGH something like 1 ounce or maybe even less. That’s what you need to put on the label.

      To figure it out, put the container on the scale and tare it to 0 weight. Then fill it with the balm. THAT’s the weight to put on the label.

      1. Sarah Davis

        Thank you so much for clarifying this for me. I was so confused about that! I will weigh my tallow balm and change my labels to show the weight. Thank you for explaining this to me!

      2. Mimi

        I have a question, I make small containers of lip scrub. When I measure it says 1.41 oz. I remember you said when calculating, don’t use decimals; round down to the next whole number. So should I put 1oz, I guess I am worry more on the fact that it’s not the exact measurements.

      3. Marie Gale

        If you are hand filling, it’s sometimes hard to get it accurate to the 100th of an ounce; You can round down to one decimal. Keep in mind that lip scrub is solid (or semi-solid) so it should be measured by weight (and it needs to say “Net wt” or “net weight” in the net quantity statement).

  7. Aguru

    Thank you very much, Marie!

  8. Aguru

    But you still need to place quantity declaration somewhere on the inner packaging? Am I right?

    I thought 21 CFR section 701.13(f)(2) meant you do not need to place quantity declaration on inner packaging at all. But I guess I was wrong.

    1. Marie Gale

      Yes, the inner container still needs the product name, identity, net contents, business name and address, and directions for safe use. The ingredient declaration is NOT required on the inner container.

  9. Aguru

    21 CFR section 701.13(f)(2):
    In the case of a cosmetic that is marketed with both outer and inner retail containers bearing the mandatory label information required by this part, and the inner container is not intended to be sold separately, the net quantity of contents placement requirement of this section applicable to such inner containers is waived.

    Does it mean you do not need to declare quantity on inner container at all?
    Or does it mean you do not need to place quantity declaration on the FRONT panel of inner container?

    1. Marie Gale

      The placement is specified in the first paragraph of 21 CFR 701(f) which says: “It [the net content] shall be placed on the principal display panel within the bottom 30 percent of the area of the label panel in line generally parallel to the base on which the package rests as it is designed to be displayed.”

      So on the inner container you don’t need to place it in that position. Note that the inner container doesn’t have a principal display panel.

    2. Bibi

      Super helpful info, thank you. “A firmly attached label” can that be something like a trifold that’s attached to the bottom of a jar with a clear sticker, to where when a person peels the sticker, the trifold can be read, but still attached to the bottom of the jar on the end side of the trifold? And if this is allowed, what MUST still be displayed on the jar itself if anything? Thank you!

      1. Marie Gale

        One of those little trifold labels (like is used on drug packaging to make space for all the information) could be used. If you are talking about a trifold brochure (as is described in printing) then no.

        What MUST be visible on the front is the product name, identity, and net contents. Data that needs to go on an informational panel (business name and address, ingredient declaration, directions, etc.) could go on a folded, attached label, so long as the person could read all the information PRIOR to purchase.

  10. With so much needed on labels, how do you manage to put that on small bottles? Many can’t read it, anyhow…does it matter if they can read it?

    1. Marie Gale

      Well, the information does have to be readable (under “normal circumstances for a typical consumer” (whatever that means!).

      However, if there really isn’t enough room on the container, the information can be placed on a firmly attached tag or card.

  11. Dottie Simmons

    Back in the 1980s or 90s we had the local ag (?) folk approach us about our product labels. The rules were as you state above, terminology and bottom 1/3 or front face of label – but also that there had to be space equivalent to 2x the font size above it. Is that still the case as well?

    1. Marie Gale

      Yes. Those requirements are still in place. In the bottom 30% of the label, parallel with the bottom of the label, with clear space above and below equal to the height of an upper case “N” of the font used, and clear space to each side equal to the width of two upper case “N”s.

  12. Norma

    Can we do a 4-5 oz or do we need to be specific?

    1. Marie Gale

      It has to be specific. No “approximate” or “estimated” or a range. (That’s specifically disallowed.)

  13. Evangeline Boyles

    So when you’re lotion is so thick it’s not pourable (I have to spoon it into my jars) I should use…
    I have always used net weight. Am I incorrect?

    1. Marie Gale

      Yes. If the product is not pourable then it’s generally considered “semi-solid.” However, if the container is a bottle and the product is squeezed out rather than scooped out, it’s kind of middle ground. Could go either way. If you are doing a not-pourable lotion by weight, that should be fine. Just make sure that the weight is measured for how much product is actually in the tube or bottle, not how much the tube or bottle holds by volume.

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