Choosing the right empty capsule size affects how much powder each capsule holds, how easy the finished capsule is to swallow, and which tooling your capsule filling machine needs. This guide gives you the full capsule size chart from 000 (largest) down to 5 (smallest), explains how fill capacity actually works, and walks through how to pick the right size for your formula and production setup.
Capsule Size Chart (000–5): Dimensions & Volume
Empty hard capsules follow a standardized numbering system used across the industry. The lower the number, the larger the capsule: 000 is the largest standard size and 5 is the smallest. These sizes are consistent across gelatin, HPMC (vegetarian), and Pullulan capsules, and most capsule filling machines are built around them.
The figures below are typical, approximate industry-standard dimensions. Exact measurements vary slightly by manufacturer and capsule material, so treat them as close reference values rather than universal specs.
| Size | Outer diameter (mm, approx) | Locked length (mm, approx) | Volume (mL, approx) | Approx. powder capacity* |
|---|---|---|---|---|
| 000 | 9.9 | 26.1 | 1.37 | ~800–1,400 mg |
| 00 | 8.5 | 23.3 | 0.95 | ~570–950 mg |
| 0 | 7.6 | 21.7 | 0.68 | ~400–680 mg |
| 1 | 6.9 | 19.4 | 0.50 | ~300–500 mg |
| 2 | 6.4 | 18.0 | 0.37 | ~220–370 mg |
| 3 | 5.8 | 15.9 | 0.30 | ~180–300 mg |
| 4 | 5.3 | 14.3 | 0.21 | ~125–210 mg |
| 5 | 4.9 | 11.1 | 0.13 | ~80–130 mg |
*Powder capacity is approximate and depends heavily on the bulk density of your material. The ranges above assume a typical bulk density of roughly 0.6–1.0 g/mL. Your actual fill weight will differ based on your specific powder — see the calculation below.
How Capsule Capacity Actually Works
A capsule's volume is fixed, but the weight it holds depends entirely on how dense your powder is. The relationship is simple:
Fill weight (mg) ≈ Volume (mL) × Bulk density (g/mL) × 1000
So the same size 0 capsule (0.68 mL) holds very different amounts depending on the material packed into it:
| Size 0 capsule (0.68 mL) | Bulk density | Approx. fill weight |
|---|---|---|
| Light, fluffy powder | 0.6 g/mL | ~410 mg |
| Average blend | 0.8 g/mL | ~545 mg |
| Dense powder | 1.0 g/mL | ~680 mg |
This is why two brands can use the same capsule size and still end up with different fill weights. The most reliable way to confirm capacity for your formula is to weigh a few test fills of your actual powder — the chart gets you in the right range, and your own measurement confirms it.
How to Choose the Right Capsule Size
Three practical factors drive the decision:
1. Your target fill weight
Start with how many milligrams of powder you need per capsule, then use the formula above with your powder's density to find the volume you need. Match that volume to the closest size in the chart. If your target lands between two sizes, sizing up avoids overfilling and tamping problems.
2. Your ingredient's density and bulk
Light, bulky powders take up more volume per milligram, so they often need a larger capsule than the raw milligram figure suggests. Dense powders fit more weight into a smaller shell. If your formula is bulky, plan for a larger size or accept more capsules per serving.
3. Swallowability
Larger capsules hold more but are physically longer and wider. Sizes 0 and 00 are the most widely used because they balance a useful fill volume against a size most people find manageable to swallow. Smaller sizes (3–5) suit low-fill formulas; larger sizes (000–00) suit higher-fill formulas where fewer capsules per serving is the priority.
Capsule Size and Your Filling Machine
Capsule size isn't only a packaging choice — it determines the tooling your filling equipment uses. Filling machines are built around a specific size via size-matched change parts:
- Manual capsule fillers use a size-specific plate (for example a 100-hole plate is drilled for one capsule size). Filling a different size means using a plate made for that size.
- Semi-automatic and automatic machines use size-specific change parts/tooling. Switching sizes means swapping to the tooling set for the new size.
If you expect to run multiple capsule sizes, factor the cost of additional plates or tooling sets into your equipment plan from the start. When you choose a machine, confirm which size it ships configured for and which additional sizes are available.
For help matching size to equipment, see our guides on manual vs semi-auto vs automatic capsule filling machines and how to choose a capsule filling machine for a supplement startup. You can also browse machines by type: manual, semi-automatic, and automatic capsule filling machines.
Practical Fit by Size
A quick way to think about where each size lands in commercial production:
| Size range | Relative fill volume | Typical use |
|---|---|---|
| 000 – 00 | Larger fill volume | Higher-fill formulas where fewer capsules per serving is the goal |
| 0 – 1 | Mid-range fill volume | The most widely used general-purpose sizes |
| 2 – 3 | Smaller fill volume | Lower-fill formulas and more compact finished capsules |
| 4 – 5 | Smallest fill volume | Low-fill, sample, and R&D applications |
Capsule Sizes Available at Leadlife
Leadlife supplies empty capsules across the standard size range in multiple materials:
- Empty gelatin and HPMC vegetarian capsules in retail counts across sizes 000–5.
- Enteric (acid-resistant) capsules in gelatin and HPMC, designed for delayed release.
- Pullulan vegetarian capsules, typically offered in the most common commercial sizes.
- Bulk and wholesale quantities in the highest-demand sizes (000–1).
Browse the full selection on the empty capsules collection. If you only need a small amount for testing or R&D, see capsules in small quantities. If you're buying capsules and a filler together, the capsule + filler bundles pair matched sizes for you.
Frequently Asked Questions
What is the most common capsule size?
Sizes 0 and 00 are the most widely used in supplement production because they balance a useful fill volume against a size most people find manageable to swallow.
What's the difference between size 00 and size 0?
Size 00 (about 0.95 mL) holds noticeably more than size 0 (about 0.68 mL) — roughly 40% more volume. Size 00 lets you fit a given amount of powder into fewer capsules, while size 0 produces a smaller, easier-to-swallow capsule.
How much powder fits in a size 0 capsule?
A size 0 capsule holds about 0.68 mL. Depending on your powder's bulk density (roughly 0.6–1.0 g/mL), that's approximately 400–680 mg. Weigh a few test fills of your own powder to confirm the exact figure for your formula.
Does capsule size affect which filling machine I need?
Yes. Filling machines use size-specific tooling — a plate on a manual filler, or change parts on semi-automatic and automatic machines. Running a different size means using the tooling made for that size.
Can I run gelatin and HPMC capsules in the same size?
The size numbering is the same across gelatin, HPMC, and Pullulan, so a machine set up for a given size can generally run that size in different materials. Some materials may need minor handling adjustments, so follow the equipment guidance for your machine.
Find the Right Capsule for Your Fill
Use the chart to land on the right size, then confirm with a quick test fill of your own powder. When you're ready, browse empty capsules in gelatin, HPMC vegetarian, enteric, and Pullulan, or reach out and tell us your fill weight, powder type, and volume — we'll help you match the right size and the right capsule filling equipment for commercial production.