First-time capsule purchasers typically pick size 00 because it looks standard. Then they find out their dose does not fit, or their powder is too fluffy, or their capsule filler only accepts certain sizes. One wrong assumption and you are sitting on 1,000 capsules you cannot use.
We have been helping people make their own supplements at home since the beginning, trusted by over 100,000 customers who choose to know exactly what is in their supplements rather than take a label at face value.
In this article, we’ll examine how to use a capsule size chart to match your dose correctly, how to choose between gelatin and vegetarian options, and how capsule size affects what your filling machine can do.
A capsule size chart tells you volume. What it does not tell you is how much of your specific powder actually fits inside that volume. That depends on density, which varies widely among powders. Turmeric packs tightly. Lion's mane mushroom powder is light and airy. The same-size capsule holds nearly twice the weight of a dense powder as of a fluffy one.
This matters when you are working backward from a target dose. Say you want 500mg of magnesium glycinate per capsule. At its typical bulk density, a size 00 capsule holds roughly 400-500mg of magnesium glycinate powder, making it a reasonable fit. Lion's mane, being less dense, may require a size 000 to hit a similar weight target.
Start with your target dose in milligrams. Then look up the bulk density of your specific powder. From there, Empty Capsule Sizes gives you the volume in milliliters, and the math is straightforward: dose in grams divided by density in g/ml equals the volume you need. Pick the capsule size that meets or slightly exceeds that number.
Any capsule size guide worth reading will tell you the size numbers are the same across both capsule types. What most skip over is that the material affects how the capsule behaves during filling, storage, and digestion. Here is what actually differs between the two:
Gelatin capsules dissolve faster in stomach acid, typically within 20 to 30 minutes. Vegetarian capsules made from hydroxypropyl methyl cellulose (HPMC) dissolve more slowly, typically within 30 to 45 minutes (Drug Development and Industrial Pharmacy, 2007). If you are sensitive to timing or taking certain powders, that difference is worth knowing before you choose.
Gelatin becomes sticky or brittle in high humidity, which affects how cleanly capsules fill and close (Pharmaceutics, 2025). Vegetarian capsule information indicates that HPMC performs better in humid conditions, making vegetarian capsules the more stable choice for warm or coastal climates (Pharmaceutical Science and Technology, 2021).
Gelatin is derived from animal collagen, which matters if you follow a vegetarian, vegan, or halal diet (DARU Journal of Pharmaceutical Sciences, 2017). When comparing capsule sizes between gelatin and vegetarian options, sourcing is often the factor that determines the decision. Our Gelatin Capsule Information page provides a complete material breakdown.
Not every capsule size works with every filling machine, and assuming otherwise is one of the more frustrating mistakes to make mid-batch. The capsule size has to match the tray hole size, or it will not fill cleanly. Here is what to confirm before you order:
Our CAPSULE-IT Original and Pro Series 400 work with sizes 000, 00, 0, and 1. Before ordering, cross-reference a capsule capacity chart to confirm your dose fits within the volume those sizes offer. Sizes 2 through 4 are not compatible with the machine and would need to be filled by hand.
Standard capsules come joined at the cap and body. Pre-separated capsules come already pulled apart, which is how the filling machine needs them loaded. Using joined capsules in a machine tray slows the process and can cause uneven fills. Our piece on Why You Should Fill Your Own Capsules covers how to set up an efficient filling workflow from the start.
The body loads downward into the tray. The cap gets pressed down to close after filling. If the capsule is even slightly too large for the tray hole, the fill will be uneven. Always confirm size match before starting a batch.
Picking the right capsule comes down to three things working together: your target dose, your powder's density, and the equipment you are filling with. Get those three aligned and the rest of the process is straightforward. Material choice, whether gelatin or vegetarian, adds another layer worth thinking through depending on your diet, your environment, and how much the sourcing of every component matters to you.
We carry the capsules, powders, and filling machines to put all of this into practice at home, without fillers, without guesswork, and at a fraction of what store-bought supplements cost. Our pill capsule size chart and full capsule lineup are there when you are ready to act on what you have learned here. You now have what you need to make a decision you can stand behind.
Size 00 is the most widely used. It fits most standard doses and works with the CAPSULE-IT filling machine, making it the practical starting point for most home setups.
No. The CAPSULE-IT Original and Pro Series 400 work with sizes 000, 00, 0, and 1 only. Sizes 2 through 4 need to be filled by hand.
Size does not directly affect absorption. The capsule material does. Gelatin dissolves faster than vegetarian HPMC capsules, which may affect how quickly the powder reaches digestion.
Size 00 holds 0.95ml. Size 0 holds 0.68ml. If your dose sits between the two, size 00 is usually the safer choice to avoid needing multiple capsules.
Yes. The sizing system is standardized across both materials. The difference is in the material, dissolution rate, and sourcing, not the dimensions.
Divide your target dose in milligrams by your powder's bulk density in g/ml. That gives you the volume you need. Match it to a capsule size using a capsule size chart.
You can, but there is little reason to. Mixing materials introduces slight differences in dissolution timing and makes sourcing documentation less clean if you are labeling your supplements.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
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