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.

Comments

  1. 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. Author

      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 as weight, that should be fine. Just make sure that the weight is measured for how much is actually in the tube or bottle — not how much the tube or bottle holds by volume.

    1. Author

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

  2. 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. Author

      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

  3. 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. Author

      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.

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