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Empty Capsule Sizes 000–5: Dimensions, Volume and Fill Weight
Capsule size is a volume, not a weight. Two powders of the same dose can need different capsules because their bulk densities differ by a factor of two. This page gives the dimensions for every standard size, the fill weight at three densities, and a calculator for your own powder.
Dimensions and volume
| Size | Closed length (mm) | Outer diameter (mm) | Volume (mL) | Wall thickness (mm) | Empty shell (mg) | Typical use |
|---|---|---|---|---|---|---|
| 000 | 26.1 | 9.5 | 1.37 | 0.09–0.12 | 163 | Large-dose blends, multi-pellet fills |
| 00 | 23.3 | 8.2 | 0.95 | 0.09–0.12 | 123 | High-dose single actives, herbal extracts |
| 0 | 21.7 | 7.3 | 0.68 | 0.09–0.12 | 96 | Most common — general pharma and supplements |
| 1 | 19.4 | 6.6 | 0.50 | 0.09–0.12 | 76 | Standard dose |
| 2 | 17.6 | 6.1 | 0.37 | 0.09–0.12 | 61 | Small to medium dose |
| 3 | 15.9 | 5.6 | 0.30 | 0.09–0.12 | 48 | Small dose, pet and veterinary |
| 4 | 14.3 | 5.1 | 0.21 | 0.09–0.12 | 38 | Micro-dose, high-value actives |
| 5 | 11.1 | 4.8 | 0.13 | 0.09–0.12 | 28 | Very small dose, paediatric and pet |
Outer diameter is measured at the cap. At the joint the body runs about 0.2–0.3 mm smaller. Wall thickness is given as the range we hold across the eight sizes; the per-size target is set on the drawing and is 0.08–0.11 mm depending on size and material.
Fill weight at three densities
Practical fill weight in mg, assuming 90% fill. Read down the column that matches your powder.
| Size | 0.6 g/mL (light) | 0.8 g/mL (typical) | 1.0 g/mL (dense) |
|---|---|---|---|
| 000 | ≈825 | ≈1,095 | ≈1,400 |
| 00 | ≈580 | ≈750 | ≈945 |
| 0 | ≈410 | ≈540 | ≈670 |
| 1 | ≈290 | ≈390 | ≈475 |
| 2 | ≈220 | ≈290 | ≈350 |
| 3 | ≈165 | ≈225 | ≈265 |
| 4 | ≈120 | ≈160 | ≈195 |
| 5 | ≈78 | ≈104 | ≈130 |
fill_rate: 0.85–0.90 manual / semi-auto · 0.90–0.95 automatic with tamping
Calculate for your powder
Three things that catch buyers out
Size 2 has two published lengths
17.6 mm and 18.0 mm both circulate as the closed length of a size 2 capsule. Ours is 17.6 mm. If you are designing a package or a machine change part, confirm against the drawing rather than a chart.
HPMC holds less than gelatin
At the same nominal size the plant shell is roughly 6% lighter on fill — size 00 takes about 710 mg against 750 mg for gelatin at 0.8 g/mL. The two are not interchangeable on a fixed fill weight.
Small sizes lose more to geometry
The shoulder and the cap joint take a bigger share of a size 4 than of a size 00. On sizes 3 and 4 the practical fill typically runs 8–10% below volume × density.
Common questions
What is the fill weight of a size 0 capsule?
A size 0 capsule holds 0.68 mL. At 0.8 g/mL and 90% fill that is about 490 mg; at 95% fill, about 520 mg. The figure of 540 mg that circulates in price lists assumes full volume at 0.8 g/mL. Measure your own powder before you fix a label claim.
How do I calculate capsule fill weight?
Volume in mL × bulk density in g/mL × fill rate × 1000 gives milligrams. Use tapped density for powders that settle, and remember that loose and tapped density can differ by 20–40% — which is the difference between size 0 and size 00.
Do capsule sizes differ between manufacturers?
Yes. Dimensions follow industry convention rather than a mandatory standard, and volume can differ by around 5% between suppliers of the same nominal size. Qualification on your own filling line is the only reliable test.
Can I use the same fill weight for HPMC and gelatin?
No. HPMC holds roughly 6% less by weight at the same size, and the body length can differ too. Keep a separate fill-weight table for each material and price them separately.
What is the closed length of a size 2 capsule?
17.6 mm on our drawing, with a 6.1 mm outer diameter and 0.37 mL volume. Some published charts show 18.0 mm. Confirm before designing around it.
Why is my real fill weight lower than the calculation?
Production never fills the shell completely: powder cannot reach the tapered end, the machine leaves headspace and the shoulder takes a share. On small sizes the loss reaches 8–10%.
Send us your dose and bulk density.
We will confirm the size, the shell material and the fill weight, and tell you what the theoretical table does not.
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