mg/kg to mL Calculator
Dose calculations
Calculate a weight-based liquid dose
Choose whether the order is written per dose or per day, enter weight in kg or lb, then use the exact medicine concentration shown on the label.
Use the amount ordered for one dose
Enter the amount prescribed for one dose.
Use the medication weight required by the order or clinical reference.
Pounds are converted to kilograms before the dose is calculated.
How is the medicine strength written?
Use the concentration of the exact liquid medicine being prepared or administered.
Calculate a liquid medicine volume from an mg/kg per-dose or mg/kg/day order, using weight in kg or lb and the exact product concentration.
Weight-based formula, examples and safety guidance
Review per-dose and per-day formulas, pounds-to-kilograms conversion, worked examples, and safety checks.
Weight-based formula, examples and safety guidance
Review per-dose and per-day formulas, pounds-to-kilograms conversion, worked examples, and safety checks.
How to Calculate mg/kg to mL
First match the calculator mode to the order. A per-dose order gives the weight-based amount for one administration. A per-day order gives a daily total that must be divided by the prescribed number of administrations.
- Step 1: Enter the order as mg/kg per dose or mg/kg/day.
- Step 2: Enter the medication weight in kg or lb. Pounds are converted to kg.
- Step 3: For a daily order, divide total daily mg by the prescribed doses per day.
- Step 4: Divide mg per dose by the concentration in mg/mL to calculate mL per dose.
If the label is written as mg per 5 mL or mg per another volume, enter both label values. The calculator converts the label to mg/mL before calculating the dose volume.
mg/kg to mL Formulas
Worked Examples
Per-dose order
Order 10 mg/kg per dose, weight 20 kg, concentration 50 mg/mL.
200 ÷ 50 = 4 mL per dose
Daily order in divided doses
Order 20 mg/kg/day, weight 20 kg, four divided doses, concentration 25 mg/mL.
400 ÷ 4 = 100 mg per dose
100 ÷ 25 = 4 mL per dose
Weight entered in pounds
Order 10 mg/kg per dose, weight 44 lb, concentration 50 mg/mL.
10 × 19.9581 = 199.581 mg per dose
199.581 ÷ 50 = 3.9916 mL per dose
Common mg/kg to mL Examples
10 mg/kg per dose for 20 kg at 50 mg/mL
Answer: 4 mL per dose
15 mg/kg per dose for 18 kg when the label says 250 mg/5 mL
Answer: 5.4 mL per dose
20 mg/kg/day for 20 kg in 4 doses at 25 mg/mL
Answer: 4 mL per dose
10 mg/kg per dose for 44 lb at 50 mg/mL
Answer: Approximately 3.99 mL per dose
These are arithmetic examples only. They are not dose recommendations. Always check the ordered medicine, patient weight, concentration, frequency, and maximum dose limits.
Practice Questions
Question 1: Order: 8 mg/kg per dose. Weight: 25 kg. Concentration: 40 mg/mL. How many mL per dose?
Answer: 8 × 25 = 200 mg. 200 ÷ 40 = 5 mL per dose.
Question 2: Order: 30 mg/kg/day. Weight: 12 kg. Give in 3 divided doses. Concentration: 20 mg/mL. How many mL per dose?
Answer: 30 × 12 = 360 mg/day. 360 ÷ 3 = 120 mg per dose. 120 ÷ 20 = 6 mL per dose.
Question 3: Order: 5 mg/kg per dose. Weight: 66 lb. Concentration: 25 mg/mL. How many mL per dose?
Answer: 66 lb × 0.45359237 = 29.94 kg. 5 × 29.94 = 149.69 mg. 149.69 ÷ 25 = approximately 5.99 mL per dose.
Question 4: Label: 125 mg/5 mL. What concentration is used in the calculator?
Answer: 125 ÷ 5 = 25 mg/mL.
When This Calculator Is Used
- •Weight-based liquid dosing written per dose or per day
- •Converting kg or lb into the kilogram weight required by an mg/kg formula
- •Dividing an mg/kg/day order into the prescribed number of doses
- •Converting a calculated mg amount into mL using mg/mL or mg per X mL labels
Clinical safety note: Always confirm whether the order is written per dose or per day, the prescribed number of divided doses, the required medication weight, product concentration, maximum-dose limits, route, and local protocols. This calculator supports calculation checking but does not recommend doses or replace clinical judgement.
Frequently Asked Questions
Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.
Continue calculating
Related weight-based dose calculators
Use these calculators when a weight-based dose needs another dosing check, body-size estimate, or route conversion.
mg to mL Calculator
Convert a medicine dose in milligrams to mL using the supplied concentration.
Open calculatorWeight-Based Tablet Calculator
Calculate tablet quantity from a dose in mg or from a weight-based mg/kg dose.
Open calculatorIdeal Body Weight Calculator
Calculate adult clinical ideal body weight using the Devine formula in cm or feet and inches.
Open calculatorBSA Calculator
Calculate body surface area from metric or imperial height and weight using four published formulas.
Open calculatorReferences and sources
Open the formula, educational, and safety sources used for this calculator.
References and sources
Open the formula, educational, and safety sources used for this calculator.
This calculator follows standard medication calculation methods used in nursing and prescribing education, including weight-based dosing (mg/kg) and dose-to-volume conversion (mg/mL).