Medical Math Formulas and Conversions
Convert to the same units first, then apply the formula; round only the final answer.
Core conversions
| from | to | factor |
|---|---|---|
| 1 kg | lb | 2.2 lb (exam convention) |
| 1 g | mg | 1,000 mg |
| 1 mg | mcg | 1,000 mcg |
| 1 L | mL | 1,000 mL |
| 1 cc | mL | 1 mL |
| 1 teaspoon (tsp) | mL | 5 mL |
| 1 tablespoon (tbsp) | mL | 15 mL |
| 1 tbsp | tsp | 3 tsp |
Preview only. 4 more rows in this section. The full sheet also covers: Dose = Desired / Have x Quantity (D/H x Q); Weight-based single dose; mg/kg/day divided into doses; Temperature conversion; Pounds and kilograms; Metric conversions; Body mass index (BMI); Intake and output (I&O); 24-hour (military) clock; Writing doses safely.
Sources
- Clinical Nursing Skills, 11.2 Dosing (Table 11.9 Common Conversion Factors; formula, ratio-proportion and dimensional-analysis methods) · OpenStax (Rice University)
- 21 CFR 101.9 Nutrition labeling of food · Office of the Federal Register (eCFR)
- Clinical Nursing Skills, 15.4 Temperature · OpenStax, Rice University
- Body mass index (Medical Encyclopedia) · MedlinePlus, U.S. National Library of Medicine
- Calculate Your BMI (adult BMI categories) · National Heart, Lung, and Blood Institute (NIH)
- Clinical Nursing Skills, 19.2 Nursing Assessment for Fluid and Electrolytes (Fluid Intake and Output Assessment, Table 19.4) · OpenStax (Rice University)
- Clinical Nursing Skills, 11.3 Documentation of Medication Administration (Approved Abbreviations; ISMP error-prone abbreviations) · OpenStax (Rice University)