What Capsule Size for 500 mg?

There is no single capsule size that always holds 500 mg. Capsule size is determined by volume, while 500 mg is a weight. Two powders weighing 500 mg can occupy very different volumes.

Convert weight and density into volume

The basic relationship is: required volume (mL) = target weight (g) ÷ bulk density (g/mL). For example, 500 mg is 0.5 g. At a bulk density of 0.7 g/mL, the powder would require approximately 0.714 mL before allowing for real-world filling behaviour.

Why this changes capsule choice

Our approximate capsule volumes include Size 0 at 0.68 mL and Size 00 at 0.95 mL. In the 0.7 g/mL example, the calculated volume is slightly above the nominal Size 0 volume, so Size 00 would provide more nominal volume. This is an estimate, not a guarantee of fill weight.

Check before ordering

Bulk density, tapping or compaction, particle size and filling technique can all affect the actual amount that fits. Test the real formulation whenever precise capacity matters.

Compare sizes 000–5 in our Empty Capsule Size Guide.