mg/kg to mL conversion basics
How to convert a weight based plan into a measurable liquid volume using the concentration on the label. Educational only: this page does not recommend specific doses.
Safety note
What you need before you start
- Weight in kilograms (kg).
- A plan written in mg/kg (per dose or per day).
- The product concentration (often listed as mg/mL or mg per 5 mL).
- How often the dose will be given (to estimate daily exposure and check limits).
Two-step conversion
Most conversions follow the same two steps:
Step 1: mg per dose
mg per dose = (mg/kg per dose) * (kg)
If your plan is written per day (mg/kg/day), first calculate mg/day, then divide by doses per day. See mg/kg calculation basics.
Step 2: mL per dose
mL per dose = (mg per dose) / (mg per mL)
If the label is written as mg/5 mL, convert it to mg/mL first: mg per mL = (mg/5 mL) / 5.
Worked example (hypothetical)
The numbers below are made up to demonstrate the math. They are not dosing recommendations.
- Weight: 14 kg
- Plan: 6 mg/kg per dose
- Concentration: 100 mg per 5 mL (which is 20 mg/mL)
mg per dose = 6 * 14 = 84 mg mg per mL = 100 / 5 = 20 mg/mL mL per dose = 84 / 20 = 4.2 mL
After calculating the raw mL, confirm how (and whether) to round based on the measuring device and your local guidance. See rounding guidance.
Common pitfalls
- Using the wrong concentration (different strengths exist for some liquids).
- Forgetting to convert mg/5 mL to mg/mL before dividing.
- Mixing up mg and mL when communicating instructions.
- Rounding too early or rounding to a value that does not match the device.
- Not accounting for total daily exposure and maximum daily limits.
Safety checks before giving instructions
- Read the concentration on the bottle you will actually use at home or in the unit.
- Confirm the route and formulation match the plan (especially for reconstituted suspensions).
- Check for maximum daily limits when relevant. See maximum daily dose basics.
- Prefer metric devices (mL) and avoid household teaspoons.
- Use teach-back to confirm caregiver understanding.
Tools and related pages
Frequently asked questions
It is usually a two step process. First calculate mg per dose from the plan (mg/kg * kg). Then convert mg to mL using the concentration: mL per dose = mg per dose / (mg per mL).
Turn it into mg per mL first: (mg/5 mL) / 5 = mg per mL. Then use mL per dose = mg / (mg per mL). Always verify the exact concentration on the dispensed bottle.
Rounding is context dependent. Many workflows calculate in mg, convert to mL using the exact label concentration, then round the final mL to match the measuring device and local policy. If in doubt, pause and verify.
No. This page is educational and does not provide dosing recommendations. Use medication specific guidance and clinician judgment for dose selection.