Capsule Size Guide

You might be asking yourself what is the best size capsule to choose when encapsulating powders. You are right to be asking yourself this question before starting a new formulation. It is crucial to think about this before starting to produce capsules and will save time and money in the long run when done correctly. 

There are standard size capsules that are named by numerical values. They are numbered: 000, 00, 0, 1, 2, 3, 4 and 5. These sizes are the same for all types of Gelatin, HPMC and Pullulan. The majority of capsule filling machinery are manufactured to be compatible with these standard sizes.

We have put together this guide to help you choose the best size for your needs.

Below is an interactive chart to help you choose the best fit. Click on each size to highlight the specifications of that size capsule.

How to Read the Capsule Size Chart

There is a lot of information on this table so here is a key on what each section means

• Capsule Weight - The weight of the capsule when empty in milligrams
• Volume Capacity - The volume of the inside of the capsule in millilitres
• Weight Capacity by Formulation - The weight capacity of the capsule (dependant on bulk density of formulation) in milligrams 
• Overall Closed Length - The length of the capsule when it is fully closed and locked in millimetres 
• Individual Lengths - Measures the body and the cap separately
• Tolerance - The acceptable variance in dimensions

Factors to Consider

When choosing a suitable size of capsule for your purposes there is a balance between the:

Required dosage

Volume of your mix

Ease of swallowing

Type of capsule being used

Required dosage

The required dosage comes down to how much of the active ingredient or ingredients is necessary for the product to be effective. You will need to decide how much of a dose you would like to be in each capsule e.g. 1000mg of Vitamin C

This will then be combined with excipients to help the product flow through the machine. Once mixed this is known as a “mix”.

You will need there to be the correct dose of ingredient within the mix in each capsule. If there is too much for one capsule you can either try to fit the powder in one capsules or you may want to consider spreading the dose over multiple capsules. E.g. rather than 1 #000 capsule splitting it over 3 #00.

Volume of the Mix

The volume of the mix will depend on the bulk density of the powders that make up your mix. We have a tool and guide on bulk density to help calculate the bulk density of your mix. 

You need to know the bulk density of your mix so that you can work out how much active ingredient ends up in each capsule. It may result in you having to alter your mix slightly or spread the dose over more than one capsule. 

Ease of Swallowing

Sometimes the sizes can be selected simply by the physical size of the capsule. For example when choosing a capsule for a child or an animal who might not be able to swallow larger capsules. 

The reason that size 00 and size 0 are the most commonly used capsules in manufacturing is that they have adequate volume for a lot of mixes as well as being easy for humans to swallow. 

Type of Capsule

Certain capsules such as Pullulan are only available in certain sizes. Determining the type of capsule you would like to produce may dictate your choice. 

We have created this table to show the different capsules available for Geltain, HPMC and Pullulan.

What is the most popular size capsule?

The most commonly used capsule is size 00. Below is a scale of size 0 and 00 capsules next to common coins to show their scale.