Converting Package Size from Volume to Weight

Topic:

  • If you’re current package fill is in mL or fl oz, you need convert the packaging size to weight (ounces) [Tip: use the mL value]. To convert, take the density (Density = mass/volume) of your formula (g/ml or g/cm3) and multiply by 0.0353 — the result is your converted package size to ounces.

Example #1:

  • Your current/target package size is 100 mL

  • Use a beaker with progressive volume readings (i.e. 20 mL, 100 mL, 200 mL, etc) and place the beaker on a gram scale, once the beaker has been placed on the scale “tare” the scale [this will zero out the weight as if nothing is currently on the scale]

  • Begin pouring your liquid finished formulation into the beaker until you reach a level volume reading (20 mL, 100 mL, or 200 mL – doesn’t matter, just make sure the liquid lines up with a number). Let’s say you stopped filling at 20 mL

  • Once you’ve reached the 20 mL level, record the “grams” reading on the scale – let’s say it read 16.6 grams

  • This gram number is your “numerator” and the 20 mL you poured to is your “denominator”

    • 16.6 grams / 20 mL = .83 g/ml (density) [Remember: Mass / Volume = Density]

  • Now, take that density value (.83 g/ml) and multiply it by your current/target package size – ours in this example was 100 mL

    • .83 g/mL x 100 mL = 83 grams (the mL’s go away/cancel out)

  • Now convert your grams value to ounces [ 1 Gram = 0.0353 oz]

    • 83 grams x 0.0353 = 2.93 ounces

  • Success! For this formula, you now know that 100 mL also equals 2.93 ounces (weight) and you can plug this into the calculator

Example #2:

  • Your current/target package size is 500 mL

  • Put your lab beaker on the scale first and then tare the reading (zero out the scale)

  • You pour your finished formulation into the beaker and stop filling at 100 mL

  • Once poured to 100 mL, the gram value was 69.76

  • 69.76 grams / 100 mL = .6976 g/ml (density)

  • Now, we do Density x Package Size

    • .6976 g/mL x 500 mL = 348.80 grams

  • Now convert your gram value to ounces [1 Gram = 0.0353 oz]

    • 348.80 grams x 0.0353 = 12.31 ounces

  • Success! For this formula, you now know that 500 mL also equals 12.31 ounces (weight) and you can plug this into the calculator