Dosage Calculation & Measurement

Use tablets = ordered dose ÷ available strength (for example 500 mg ordered ÷ 250 mg per tablet = 2 tablets).

Only scored tablets may be split; if a result requires splitting an unscored tablet, check with the nurse or pharmacy.

Always confirm the calculated number is reasonable and safe before administering.

Use the concentration on the label: mL = ordered dose ÷ available strength, then multiply by the volume if needed.

Ratio and proportion (for example 250 mg/5 mL = 100 mg/x) reliably solves liquid problems when units match.

Measure liquids at the bottom of the meniscus at eye level using a calibrated device.

1 g = 1000 mg, so convert grams to milligrams before dividing (0.5 g = 500 mg).

1 teaspoon = 5 mL and 1 tablespoon = 15 mL for household-to-metric conversions.

Handle decimals carefully to avoid ten-fold errors, which can cause serious harm.

Read the label for drug name, strength (mg per tablet or mg per mL), and form before calculating.

Match the ordered dose and unit to the label, converting to a common unit first.

Calculate the amount for a single dose at each administration, not the daily total.