Determining Your Container's Volume
What is the volume of my container?
Method #1: Checking the Product Label
For example, the example image shows that this bottle has a volume capacity of 16 fluid ounces (or 475 milliliters). Note that 16 fluid ounces is not the same as 16 ounces. Fluid ounces are a unit of volume and ounces are a unit of weight.
Method #2: Calculating with the Nutrition Facts Label
These garbanzo beans have a net weight of 15.5 ounces (not fluid ounces), but we have no idea what the volume of this container is! Or do we?
We see that this can of garbanzo beans has a serving size of 1/2 US cup. A single 1/2 US cup is about 120mL. For a total of about 3.5 servings, we have 3.5 x 120 mL = 420mL (or ~14 fl-oz). This means that this can will fill up to around 14 fluid ounces! Use each refill product's volume calculator to figure out what volume your refill needs will require!
Can't convert tsps/tbsps/cups to mL/fl-oz? No worries! Just do a quick web search!
Method #3: Using Measuring Cups
In this case, grab some measuring cups. I like to use my 2-cup measuring cup, which also conveniently shows me the mL of whatever I am measuring.
If the container you are trying to measure the volume of is smaller than your measuring tool, it is very simple! First, I fill the container I want to measure with water, making sure not to fill to the brim in order to account for closing the container or for putting in a pump. Then I pour that water in my 2-cup measuring cup and read the volume. That's it!
If the container you are trying to measure the volume of is larger than your measuring tool, do the reverse! Fill up your measuring tool and pour into your container instead. Count the number of times you poured and add. Switch to a smaller measuring tool for more precision.
You can always convert your measuring tool units, whether it is mL, cups, tbsps, etc, as well! If you are unsure of the conversion, you can do a quick online search to find out the converted amounts.
As previously mentioned, if you have pumps or caps that will take up part of your container's volume, make sure to account for the space when you are filling up the container with water.