Dose Calculations
Dose calculation calculators for converting ordered doses into measurable amounts — including mg→mL, mL→mg, and weight-based dosing (mg/kg).
mg to mL
Convert milligrams to milliliters using concentration
mg/kg to mL Dose
Convert weight-based dose to volume per dose
mL to Units
Convert volume to units using concentration
Units to mL
Convert units to volume using concentration
How Dose Calculations Work
Dose calculations convert a prescribed amount into something you can measure and administer — usually a volume in milliliters (mL). These calculations are fundamental to safe medication administration across all healthcare settings.
The key inputs for any dose calculation are: the ordered dose (in mg, units, or per-kg units), the medication concentration or strength (often listed as mg/mL or units/mL), and sometimes the patient's weight in kilograms. Always check that all units match before calculating.
Common Dose Calculations Explained
Milligrams to milliliters (mg to mL)
Use this when you have a dose in mg and the medication strength is in mg/mL. The result is the volume to administer.
Example question:
The ordered dose is 250 mg. The concentration is 50 mg/mL. How many mL is required?
Worked example:
Dose = 250 mg
Concentration = 50 mg/mL
mL = 250 ÷ 50 = 5
Tip: Dose ÷ strength = volume.
Milliliters to milligrams (mL to mg)
Use this when you know the volume drawn up and need to confirm how many mg that contains.
Example question:
You have drawn up 3 mL. The concentration is 20 mg/mL. How many mg is this?
Worked example:
Volume = 3 mL
Concentration = 20 mg/mL
mg = 3 × 20 = 60
Tip: Volume × strength = dose.
Weight-based dose (mg/kg to total mg)
Weight-based dosing is written per kilogram. Multiply the ordered mg/kg by the patient's weight to get the total mg dose.
Example question:
The order is 8 mg/kg. The patient weighs 25 kg. What is the total dose in mg?
Worked example:
Dose = 8 mg/kg
Weight = 25 kg
Total mg = 8 × 25 = 200
Tip: Per-kg dose × weight = total dose.
When These Calculators Are Used
- •Converting ordered doses into volumes for administration (mg→mL)
- •Confirming how much drug is in a drawn-up volume (mL→mg)
- •Checking weight-based dosing calculations (mg/kg → total mg)
- •Double-checking medication math during preparation and handover
- •Teaching/studying dose calculation fundamentals
Clinical safety note: Always confirm the order, units (mg vs mcg), concentration (mg/mL), and local protocols before administration. These calculators support calculation checking but do not replace professional judgement. Examples on this page are for calculation practice only.
Related Calculator Categories
Frequently Asked Questions
Always confirm units and concentrations before calculating.