Student Success Commons: Dosage Calculations

Mastering dosage calculations is a must for anyone entering the nursing or veterinary technology fields—lives depend on it! Whether you're just starting out or brushing up on your skills, accurate dosing is a key part of providing safe, effective care. Explore the variety of resources on this page designed to boost your skills and confidence, so you’re fully prepared for clinical success.

Common Conversion Factors:

• 1 mg = 1,000 mcg
• 1 g = 1,000 mg
• 1 kg = 1,000 g
• 1 oz = 30 mL
• 1 tsp = 5mL
• 1 tbsp = 15 mL
• 1 tbsp = 3 tsp
• 1 kg = 2.2 lb
• 1 gr = 60mg
• 1 pound = 16 ounces
• 1 kilogram= 2.2 pounds
• 1 teaspoon = 5 milliliters
• 1 tablespoon = 3 teaspoons = 15 milliliters

Though these are some of the most common ones, more handy conversions are listed on this page, and on our Units and Conversions page.

General Rounding Guidelines

• For dosages less than 1.0 round to the nearest hundredth
• For dosages greater than 1.0 round to the nearest tenth

When performing calculations, do not round until calculating the final answer. Dosages of oral liquid medications for adults are typically rounded to the tenth for doses over 1 mL. For doses less than 1 mL the dosage is rounded to the hundredth.

For pediatric patients, it is important to be as precise as possible to avoid medication errors. Oral liquid medications less than 1 mL should be rounded to the hundredth.

When rounding, it is also important to use critical thinking to evaluate your final answer. For example, a drop cannot be administered as a fraction of a drop, so drops are rounded to the nearest whole number

For a refresher and some practice rounding, please check out the Student Success Commons' Rounding Rules Guide

Dose Calculation Examples and Explanations