Reference sheets · Dosage calculation formulas
Printable reference
Printable dosage calculation formula sheet
Each formula with the expression and a worked line showing the numbers going in.
Dosage calculation formulas - Dosage calculation formulas. Each formula with the expression and a worked line showing the numbers going in.| Formula | Expression | Worked line |
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| Desired over Have (D/H × Q) | Amount to give = (D ÷ H) × Q | Ordered 500 mg; on hand 250 mg tablets. (500 ÷ 250) × 1 = 2 tablets. |
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| IV drip rate (gtt/min) | gtt/min = (Volume × Drop factor) ÷ Time (min) | 1000 mL over 8 hr with 15 gtt/mL tubing: (1000 × 15) ÷ 480 = 31.25 ≈ 31 gtt/min. |
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| IV flow rate (mL/hr) | mL/hr = Volume (mL) ÷ Time (hr) | 1000 mL over 8 hr: 1000 ÷ 8 = 125 mL/hr. |
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Teaching conventions used throughout: 1 kg = 2.2 lb, 1 grain = 60 mg, 1 fl oz = 30 mL. Study reference only.
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