Nursing Measurement Equivalencies

Overview

This lecture explains the concept of equivalencies in nursing calculations and provides common conversion factors for household and metric measurements essential for clinical practice.

Concept of Equivalencies

• Equivalency means two values or quantities are the same amount (e.g., 1 cup = 8 ounces).
• Nurses must memorize common household and metric equivalents for accurate medication dosage and conversions.

Household Measurement Equivalencies

• Drop (gtt): 10, 12, 15, or 20 gtt = 1 mL; microdrop (mcgtt): 60 mcgtt = 1 mL.
• 1 teaspoon (tsp) = 5 mL.
• 1 tablespoon (Tbsp) = 3 tsp = 15 mL.
• 1 ounce (oz) = 30 mL.
• 1 cup (C) = 8 oz = 240 mL.
• 1 pint (pt) = 2 cups; 1 quart (qt) = 4 cups; 1 gallon (gal) = 4 quarts.
• 1 pound (lb) = 16 oz.

Metric Measurement Equivalencies

• The metric system is based on units of 10 (move decimal right for smaller, left for larger units).
• Meter: length, Liter: volume, Gram: weight.
• 1 kilogram (kg) = 2.2 lb = 1000 g.
• 1 cm = 0.39 in; 1 in = 2.54 cm = 25.4 mm.
• 1 liter (L) = 1000 mL = 1000 cc.
• 1 gram (g) = 1000 mg; 1 mg = 1000 mcg.
• 37°C = 98.6°F.

Standard Conversions (For Quick Reference)

• 1 tsp = 5 mL.
• 1 Tbsp = 15 mL.
• 1 oz = 30 mL.

Other Common Measurements in Nursing

• Units (U): used for drugs like insulin and heparin.
• International Units (IU): used for vitamins (e.g., Vitamin D 600 IU).
• Milliequivalents (mEq): used for electrolytes (e.g., Potassium 40 mEq).
• Percentages: describe concentrations in IV fluids (e.g., 0.9% NaCl = 9 g NaCl/1000 mL).
• Ratios: medication concentrations (e.g., Epinephrine 1:1000 = 1 g/1000 mL).

Key Terms & Definitions

• Equivalency — Two values or quantities that are the same amount.
• Metric System — System of measurement based on units of ten; includes meter, liter, gram.
• Unit (U) — Standardized measurement for certain drugs.
• International Unit (IU) — Measurement for vitamins and some drugs.
• Milliequivalent (mEq) — Measurement for electrolytes.
• Percentage — Indicates amount of solute in 100 mL or 1000 mL of solution.
• Ratio — Expresses concentration as a relation (e.g., 1:1000).

Action Items / Next Steps

• Memorize household and metric equivalents and conversions listed above.
• Complete practice problems for converting measurements.
• Review videos linked for further help with metric conversions.
• Refer to the answer key in the textbook for solutions to practice problems.