Research Outline

Capsule Sizes


To determine what the most common pill size is. This research should focus on pill capsules, not pill tablets. If possible, the output of the research should be a spreadsheet that shows the size of the capsule and how common it is. For example, "pill capsule size 00 represents 45% of all the pills, pill capsule size 0 represents 25% of all the pills, etc." If the data cannot be effectively broken down by different sizes, it's acceptable to then just provide the most common pill capsule size of them all. For example, "pill capsule size 00 is the most common pill size across all pills on the market. " Capsule size ranges can be found here.

Early Findings

  • According to insights published by LTD, a global leader in capsule manufacturing and production, "For most applications, a size 00 or size 0 will be sufficient and are often classed as standard capsule sizes. They are the most common sizes used by all because a size 0 holds about 500mg or 0.5 grams of powder while a size 00 holds about 735 mg or 0.735 grams."
  • A 2016 study of capsule sizes among the 15 most commonly prescribed medications for children in the U.S. found that the average/median pill size ranges from 15mm to 17mm in length, which appears to be most relevant to capsule sizes 2 and 3, based on this chart and this chart.
  • RxList provides a very extensive list of medications and readily identifies which of these are in capsule format.
  • Calquence is a capsule medication identified on the list above. Calquence is typically prescribed in a 100 mg capsule. Based on this chart, the capsule size would be a 4 (assuming typical powder density). This method of triangulated can be repeated across various other capsule medications to help assess which sizes are the most common.

Results of Early Findings

  • We attempted to locate direct data showing the most common pill capsule sizes, however, this information is severely lacking within publicly available information.
  • It is possible to triangulate this data by taking a sampling of capsule medications available on the market and determining their sizes.
  • One issue with this triangulation is that capsule pill sizes for specific medications do not appear to be readily available, as other measurement metrics are used instead. Despite this, we can still triangulate by looking at the amount of medication included per capsule (e.g. 100 mg) and then determining what the appropriate capsule size would be for this. Although capsule size is relevant to powder density, per this chart, for the sake of this triangulation, we will operate on the assumption of typical powder density (the middle column under the Typical Fill Weights section of the chart). As such a medication with 100 mg per capsule would equate to capsule size 4, as 5 would be too small and 3 would be double the volume needed.
  • The results of this triangulation will be added to the attached spreadsheet.

Triangulation Flow

Step 1: We will identify 150 capsule medications from this list.

Step 2: For each medication we will identify how much of the medication is dosed per capsule (e.g. 100 mg of the medication in each capsule). This can be done using a drug database such as this one or any other credible source.

Step 3: We will use the dosage per capsule to determine most likely capsule size using this chart. For the sake of this triangulation we will ignore the nuance of powder density and rely only on the 'Typical' Fill Weights column (middle column under Typical Fill Weights). For example, capsule 5 can hold 90 mg and capsule 4 can hold 145 mg so a medication with 100 mg per capsule would fall under capsule size 4, as 5 is too small.

Step 4: All data will be supplied in the attached spreadsheet.