Making your own capsules at home requires empty capsule shells, a filling device, and powdered ingredients. The process is straightforward: separate the capsule halves, fill the longer body piece with powder, and press the shorter cap back on. With a basic capsule filling tray, you can produce 100 uniform capsules in about 15 to 20 minutes once you get the hang of it.
Choosing the Right Capsule Size
Capsules come in standardized sizes numbered 000 (the largest) down to 4 (the smallest). The number you need depends on how much powder you want in each dose. Here’s what each size holds by volume:
- Size 000: 1.37 ml
- Size 00: 0.91 ml
- Size 0: 0.68 ml
- Size 1: 0.50 ml
- Size 2: 0.37 ml
- Size 3: 0.30 ml
- Size 4: 0.21 ml
Volume alone doesn’t tell you the weight of powder you’ll fit inside, because powders vary in density. A size 00 capsule holds roughly 735 mg of an average-density powder, but the actual range stretches from about 546 mg for a fluffy, low-density powder up to 1,092 mg for something very dense. If you already know the milligram dose you want, weigh a small amount of your powder in a measuring spoon or cup to get a sense of its density before buying capsules.
Size 00 is the most popular for home use. It’s large enough to deliver a meaningful dose of most supplements without being difficult to swallow. Size 0 works well if you’re sensitive to swallowing larger pills, and size 000 is best reserved for bulky powders where you’d otherwise need to take multiple capsules per dose.
Gelatin vs. Vegetable Capsules
Empty capsules are made from one of two materials: gelatin (derived from animal collagen) or HPMC, a plant-based cellulose often sold as “vegetable caps.” Both work for home filling, but they behave differently around moisture.
Gelatin shells have been the standard for decades. They’re inexpensive, dissolve quickly in the stomach, and snap together with a satisfying click. Their main weakness is humidity sensitivity. In dry conditions, gelatin can turn brittle and crack. In humid environments, the shells soften and stick together.
HPMC vegetable capsules absorb moisture faster and to a greater extent than gelatin. In controlled testing, HPMC shells gained about 2.25% of their mass within 30 minutes of humidity exposure, compared to just 0.78% for gelatin. By 24 hours, HPMC capsules had absorbed roughly 5.5% additional moisture. This makes HPMC more forgiving if your fill material contains some moisture, since the shell accommodates it rather than becoming immediately compromised. Vegetable capsules are also the clear choice if you follow a vegetarian, vegan, halal, or kosher diet.
For most home projects, either type works fine. Pick gelatin if cost is the priority and you’re storing capsules in a controlled environment. Pick HPMC if dietary preferences matter or your powder has any moisture content.
Equipment You’ll Need
You can fill capsules one at a time by hand, pulling each shell apart, scooping powder into the body, and pressing the cap on. This works for a handful of capsules but gets tedious fast. A capsule filling tray speeds things up dramatically.
The most common home model is a 100-hole tray, which holds 100 capsules in a grid. You separate all the caps in one motion, spread powder across the exposed bodies, tamp it down, then press all the caps back on at once. These trays typically cost between $20 and $40 and are sized for a specific capsule number, so make sure you buy the tray that matches your capsule size.
Larger trays exist for people filling capsules regularly. A 400-hole tray quadruples your output per batch, and 800-hole versions are available for very high-volume home production. For most people filling supplements for personal use, the 100-hole version is plenty.
Beyond the tray itself, you’ll want:
- A digital scale accurate to at least 0.01 grams, for checking capsule weights
- A tamping tool (usually included with the tray) for compressing powder
- A spreader card or flat-edged scraper for distributing powder across the tray
- Small bowls or containers for holding and mixing powder
Step-by-Step Filling Process
Prepare Your Powder
Start by weighing out the total amount of powder you need for the batch. If you’re filling 100 capsules and want 500 mg in each, you need 50 grams of powder, plus a little extra to account for waste left on the tray. Break up any clumps by pressing the powder through a fine mesh strainer or sifting it into a bowl. Clumpy powder fills unevenly and creates air pockets inside the capsules.
If your powder is sticky or cohesive, it won’t flow smoothly into the capsule holes. Adding a tiny amount of a flow agent solves this. Magnesium stearate is the most commonly used option in supplement manufacturing, and it works well at home too. Even 0.5% by weight (about 0.25 grams per 50-gram batch) noticeably improves how a sticky powder moves across the tray. Mix it thoroughly before filling.
Load and Separate the Capsules
Place empty capsules into the tray with the longer body piece pointing down into the holes and the shorter cap facing up. Most trays have a base plate and a top plate. The bodies drop into the base, and the caps sit in the top plate. Twist or lift the top plate to separate all the caps at once, exposing the open bodies ready for filling.
Fill and Tamp
Pour your powder onto the tray of open capsule bodies. Use a spreader card to push powder across the surface, working it into each hole. Don’t try to fill them completely in one pass.
After the first layer, use the tamping tool to gently press the powder down into each capsule. Apply steady, straight, even pressure across the entire tray. This is the most important step for consistency. Uneven tamping creates capsules with different weights, meaning some doses will be stronger than others. Press straight down rather than rocking or angling the tool.
After tamping, add more powder and repeat. Most batches require two to four rounds of spreading and tamping to fill the capsules completely. Keep going until the powder is level with the top of the capsule bodies.
Rejoin the Caps
Place the top plate (holding all the caps) back onto the base plate, aligning them carefully. Press down firmly and evenly until you hear or feel the caps click into place on the bodies. Remove the finished capsules from the tray.
Checking Your Accuracy
Weigh five or six capsules from each batch on your digital scale. First weigh one empty capsule (both body and cap together) to get the shell weight, then subtract that from each filled capsule’s total weight to find the powder weight. Your filled capsules should be within about 10% of each other. If the variation is larger, you’re likely tamping unevenly or not distributing powder across the tray thoroughly enough.
Keeping a simple log of your batch weights helps you improve over time. Note the powder type, capsule size, number of tamping rounds, and the average fill weight. After a few batches, you’ll dial in a repeatable process.
Storing Finished Capsules
Place your filled capsules in a dark glass container, like an amber supplement bottle, and store them in a cool, dry place. Heat and humidity are the two biggest enemies. High humidity softens gelatin shells and causes HPMC shells to absorb excess moisture, potentially affecting whatever is inside. Low humidity makes gelatin brittle and prone to cracking.
A kitchen cupboard away from the stove works well. Avoid the bathroom, where showers create humidity spikes, and skip the refrigerator unless the specific ingredient requires cold storage, since opening a cold container in a warm room creates condensation. If you live in a particularly humid climate, tossing a small silica gel packet into the storage container provides an extra layer of protection.
Homemade capsules don’t have the commercial coatings or sealed packaging that extend shelf life on store-bought supplements. Plan to use your batches within a few months, and inspect capsules before taking them. If shells look discolored, feel tacky, or have cracked, discard them and fill a fresh batch.