Liquid Medication Dosage Calculator
Calculate mL to administer for oral liquids, suspensions, and solutions using D/H × Q.
Understanding this tool
Why nurses use it
Liquid medicines — syrups, suspensions, and oral solutions — are labelled by concentration (mg/mL) rather than tablets. Nurses must convert a prescribed mg dose into millilitres to draw up the correct volume, especially in paediatrics where small errors have large consequences.
When to use it
Use for oral liquids when the order is in mg (or mcg) and the bottle label shows mg/mL. Always use an oral syringe, not a household spoon.
Calculate
How to use this calculator
- Verify the prescribed dose in mg.
- Check the bottle label for concentration (mg/mL).
- Calculate the volume to administer.
- Draw up with an oral syringe and document the volume given.
How the calculation works
Volume (mL) = (Desired mg ÷ Concentration mg/mL) × Quantity. This is the same D/H × Q logic as tablet math, but the result is millilitres instead of tablet count.
Formula used by this tool — verify units before applying at the bedside.
Worked example
Limitations & clinical notes
- Confirm concentration on the bottle label — strengths vary by product.
- Use appropriate oral syringe; avoid household spoons.
References
Key sources: WHO — Medication Without Harm.
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Disclaimer: This calculator is for educational and bedside double-check purposes only. It does not replace institutional protocols, prescriber orders, pharmacist verification, or clinical judgment. Always follow your local policies — especially for high-risk medications, infusions, pediatrics, and critical care. If the patient is acutely unwell, escalate immediately rather than relying on any calculator output.