The question of how many capsules can be filled by one teaspoon of powder is common, but it does not have a single, fixed answer. The conversion is highly variable and depends entirely on the specific properties of the substance being measured, not on the containers themselves. Since a teaspoon measures volume and a capsule’s capacity is determined by the weight of its contents, the link requires a specific measurement of the powder. Using a universal conversion chart will result in inaccurate dosing, which is problematic with potent compounds.
Understanding the Standard Volumes
A standard United States teaspoon is a unit of volume, officially defined as 4.9289 milliliters (mL). For practical purposes, it is widely accepted and standardized for nutritional labeling as 5 milliliters. This 5 mL volume is the fixed quantity being measured for the powder.
Capsules are defined by their shell size, which dictates their maximum volume capacity. Common sizes range from the large Size 00 (about 0.95 mL) to the smaller Size 0 (approximately 0.68 mL). Capsule size numbers are inversely related to their physical size; for example, a Size 1 capsule is smaller than a Size 0. Although the volume capacity of the capsule is fixed, the actual weight of powder it holds varies drastically depending on the ingredient.
The Critical Impact of Powder Density
The conversion is not constant due to powder density, which is the mass of a substance packed into a specific volume. Density measures how tightly packed the material is, affected by particle size, shape, and compressibility. For example, a fine, fluffy herbal powder has a much lower density than a coarse, granular mineral supplement.
Consider the difference between a light powder like ground cinnamon (bulk density around 0.5 g/cm³) and a dense substance like fine table salt (closer to 1.38 g/cm³). One teaspoon of cinnamon weighs significantly less than one teaspoon of salt, despite occupying the same 5 mL volume. This difference in weight directly translates to how many capsules can be filled.
The way the powder is packed also influences the amount that fits into both the capsule and the teaspoon. Powders with irregular particles can trap more air, a phenomenon sometimes called the “fluff factor,” resulting in a lower weight per volume. Tamping or compressing the powder reduces this air space, increasing the density and allowing more powder to fit into the capsule shell. The total weight of a teaspoon of powder depends on the substance’s physical characteristics and the packing method used.
Calculating the Conversion for Your Specific Substance
The only reliable way to determine how many capsules equal a teaspoon of your specific powder is to perform a direct weight measurement using precise tools. This requires a digital scale capable of measuring in milligrams (mg) and your chosen capsule size. This calculation provides an accurate ratio based on the actual density of the material.
First, measure the weight of the powder in one level teaspoon, using a standardized measuring spoon. For example, one level teaspoon of the substance might weigh 2,500 mg. Next, fill several target capsules using your preferred filling method (by hand or machine), and then weigh the contents of a single filled capsule. If a Size 0 capsule holds 500 mg of the powder, you have the two weight figures needed for the conversion.
The final step is a simple division: divide the weight of the powder in the teaspoon by the weight of the powder in one capsule. Using the example figures, 2,500 mg divided by 500 mg equals 5, meaning one teaspoon of that specific powder would fill five capsules. Due to wide variations in density, the conversion should never be guessed, especially when accurate dosing is required.