Botulinum toxin (BoNT) therapy involves as much art as it does science. Prescription and injection of a BoNT product requires that clinicians be familiar with the unique properties of each product, including its dosage range for a seemingly ever-expanding list of approved or published medical indications. This quick reference guide provides detailed dosage information for the four BoNT products available in the USA (abobotulinumtoxinA, incobotulinumtoxinA, onabotulinumtoxinA, and rimabotulinumtoxinB) which are approved for both cosmetic and medical indications. Included in this abbreviated manual are updated regulatory agency approved medical indications for both adults and children and recommended dosage ranges in the USA (Food and Drug Administration), Canada (Health Canada), the United Kingdom (Medicines & Healthcare products Regulatory Agency), and the European Union (European Medicines Agency). Detailed BoNT dosage information for each of these BoNT products is presented in an easy-to-navigate table format. The tables are organized by clinical indication along with each agency-approved dosage where available and the published dosage ranges per treatment session and per structure injected. Providing this information in a single reference manual allows clinicians to quickly calculate the dosage of a given BoNT product for a given indication and/or structure. The anatomical illustrations provided in this manual serve as a reference guide for clinicians to enhance the localization of muscles and other target structures during the injection planning process. The authors hope this information will be useful for clinicians and for the patients to whom they provide care.