Follow Up : Understanding Standard and Overflow Capacity

Follow Up : Understanding Standard and Overflow Capacity


This week let’s follow up on Packaging Crash Course’s article back in February “What is the difference between standard and overflow capacity?”. We’ve discuss the definition of both and how understanding the difference of these two measurement can help you finding the bottle that fits your fill application. But first, let’s review some of the common size conversion as we have been getting a lot of questions about what 8oz equates to in ml, or how many oz in a gallon. Below is a short list of common fluid volume conversions:

Standard Size Size in oz Size in ml Size in cc Size in Liter Size in Gallon
2oz 2 59.1471 59.1471 0.0591471 0.015625
250ml 8.45351 250 250 0.25 0.066043
1 Liter 33.814 1,000 1,000 1 0.264172
2dram 0.25 7.39338 7.39338 0.00738338 0.00195313

Quick Convert – The Google Way

If you are not familiar with this functionality, you should give this tool a try. Google has an unit converter embedded to their search engine. Next time when you are at google, simply type the desired conversion into the search box in the following format:

convert 250ml to oz

Google will immediately display an editable conversion calculator at the top of their search results screen that looks like this:

Google Unit Conversion Calculator
Google Unit Conversion Calculator

You can edit the conversion for additional conversions, Google also allows you to switch between different unit display so you can get your answer quicker. It’s a pretty useful tool that includes most fluid and volume measurements.

How Does This Benefits Our Conversation About Overflow Capacity?

As discussed in our Packaging Crash Course article, overflow capacity is the maximum volume of a bottle if the contents were filled to the brim. So if you are looking to fill 250ml of liquid in an 8oz stand capacity bottle, depending on it’s overflow capacity, you might be able to fill it without much head space trouble. There are many “8oz” bottles out there with an overflow capacity of 260ml to 275ml. In those cases it is worthwhile to sample those bottles and conduct a fill test to ensure the desired amount of head space remains. Fill testing is critical especially when you are installing a lotion pump or sprayer that will take up internal space of the bottle.

That’s super simple, but what’s OFC and how it is useful for me?

Per our previous Packaging Crash Course article suggests, standard capacity is a normal volume of a bottle when it is filled to the shoulder area of the bottle. For jars that doesn’t have a shoulder feature, it will often filled close to the top with reasonable amount of headspace available. Overflow capacity, or OFC, comes in handy if you want to know the exact volume of liquid the bottle can hold if it is filled all the way to the brim. It is the actual capacity of the bottle. For example, back to the 60cc Amber Pour-Out glass bottle in our first example. The specification indicate this bottle has an OFC of 66.6cc, which means if filled to the brim, the bottle can hold a total of 66.6cc.

OFC is useful when you are trying to be accurate in your fill compares to the your label claim. If your label claim states 2 fl. oz. this 60cc Amber Pour-Out bottle will comfortably fill 2 fluid ounce of liquid as the exact conversation of 2oz is 59.1471cc. Which means if you fill 2 fl. oz. of liquid in a this bottle, you will have enough headspace to compensate for liquid expansion as the ambient environment temperature raises, and the LDPE cone liner that the Plastic Phenolic cap this bottles comes with, which takes up some space in the bottle itself, can comfortably fit with your product without overflowing.

Things gets hairy when you are trying to fill 250ml (or 250cc) of liquid in a 8oz bottles. While some 8oz bottle do comfortably fill 250cc liquid as it’s OFC are in the 270cc range, some do not. If you examine the actual conversion, you will discover that 8oz only converts to 236.588cc. Therefore, you must carefully examine the OFC of a particular 8oz bottle to determine whether it is compatible with your 250cc label claim application. One of our 8oz amber Boston Round, for example : http://www.bottlestore.com/bottles-containers/glass-containers/glass-bottles/8oz-amber-boston-round-glass-bottle-24-400-neck.html?, only has an OFC of 247.2cc, which is not suitable for 250cc label claim products. On the other hand, our bulk packed 8oz amber Boston Round : http://www.bottlestore.com/bottles-containers/glass-containers/glass-bottles/8oz-amber-boston-round-glass-bottle-24-400-neck-1.html, manufactured by a different factory, has a OFC of 255.1cc. While tight, it can hold 250cc liquid.

How can I find out my bottle’s OFC?

Overflow capacity are generally stated in the manufacturer’s technical drawing document. It is often listed in the drawing in the notes section. You can simply write to the company you bought the bottle form to obtain the technical drawing. Make sure you have the SKU number handy as different SKU number often reference a different bottle, so you want to make sure the technical drawing you obtains reference the same bottle you have in your hand. If technical drawing is not available, you can use a simple kitchen weight to determine OFC if the weight gives you the unit of measure you desired. Simply weight the bottle with water filled to the brim, then empty out the bottle and weight it again. The difference between two weight is your OFC. Please note that manufacturers always have a reasonable range of tolerance in it’s OFC measurement, so if you happened to measure 265.35cc and the technical drawing listed 265.30cc +/- .15cc, it is within it’s listed tolerance and there is nothing to fear.

For BottleStore, we seek to display all available OFC figures for the glass and plastic bottles, jars, and jugs we sell. It is measured in the “Additional Information” section of a particular product listing. If you have questions about our bottle’s OFC, simply give us a call at 866.BUY.BTLS.

Fill Test With Product Samples

As a general rule of thumb, we always encourage you to fill test your product with the bottle you have picked out to ensure compatibility and to ensure the proper amount of head space is available after the fill. Fill test also confirms your volume label claim if you are displaying the volume of product the bottle has. We offer a free sampling program for most bottles that can help you archive this goal. Simply click on the “Order Sample” button on individual product detail page (if applicable) and we will send you a sample of the product, free of charge, to ensure compatibility. Terms, conditions, and restrictions are displayed on the sample ordering page.

Order Sample functionality
Sample ordering functionality on BottleStore.com

How Can We Help?

If you have questions about overflow capacity for a particular item we offer, or general questions about unit conversion, call us at 866.BUY.BTLS. We stand ready to help you.


Jonathan @ BottleStore
Jonathan @ BottleStore
Jonathan is the Online Marketing Manger of BottleStore and it's parent - The O.Berk Company. In addition to making BottleStore work and run smoothly, Jonathan also enjoys passing on packaging knowledge to help solve customer pain points. He is the chief architect of Packaging Crash Course - a packaging resource hub for rigid glass and plastic packaging site.


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