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Tablet & Capsule Dose Calculator

Calculate how many tablets or capsules to administer from an ordered dose.

Formula

tablets = ordered dose ÷ dose per tablet

What the prescriber wrote

Strength on the label

Result

Enter values above to calculate.

Worked example

Scenario: Order: Lisinopril 20 mg PO daily. Available: Lisinopril 10 mg tablets.

  1. 1Identify the ordered dose (20 mg) and the dose per tablet (10 mg).
  2. 2Divide ordered by per-tablet: 20 ÷ 10 = 2.

Administer 2 tablets.

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When to use this calculation

Use this calculation any time the ordered dose doesn't match a single available tablet or capsule strength — for example, when the order is 50 mg but tablets come in 25 mg, or when the order is 0.125 mg but the available strength is 0.25 mg (give half a tablet). It's the simplest and most-tested dose calc on the NCLEX.

Common errors to avoid: confusing milligrams with micrograms (1 mg = 1000 mcg — read labels carefully), giving fractional tablets that aren't scored (only scored tablets can be split safely), and trusting the calculation when the result is a non-standard fraction (1.3 tablets usually means the order or available strength was misread). If the math gives anything other than a whole or half tablet, stop and verify the order.

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