Medical Dosage Converter

Convert between mg/kg, µg/kg, mg, and weight-based dosing references — an educational tool for understanding dose units.

Medical Dosage

mg/kg, μg/kg, IU

From

Result

1000

1 mg/kg = 1000 μg/kg

Popular conversions

What Is a Medical Dosage Converter?

A medical dosage converter translates dose-related units — milligrams per kilogram to micrograms per kilogram, and weight-based doses into total amounts. Many medications, especially for children, are dosed by body weight (mg/kg), so a patient's weight turns a per-kilogram rate into a total dose. This tool converts the units involved to help students and professionals understand and check those relationships.

This converter routes through base SI units and is strictly educational — it is not a prescribing tool and does not account for drug-specific factors, maximum doses, formulations, or clinical judgement. Always rely on a qualified prescriber, the drug's labelling, and institutional protocols for any real dosing decision. Use this to learn the unit math, not to determine a patient's medication.

This is one category of the full Unit Converter — pair it with our percentage calculator or scientific calculator for related everyday maths.

How Dosage Unit Conversion Works

Weight-based dosing

A dose in mg/kg multiplied by body weight in kg gives the total dose in mg. This is the core relationship behind paediatric and many adult doses.

Prefix steps of 1,000

1 mg = 1,000 µg; 1 µg = 1,000 ng. Potent drugs are dosed in micrograms, so prefix care is critical to avoid 1,000-fold errors.

Total dose from a rate

Per-kilogram rates need the patient's weight to become an absolute amount. The converter handles the unit math, not the clinical inputs.

Units only — not a prescription

The tool converts units. It does not apply maximum doses, drug concentrations, or clinical context — those require a professional.

Core Dosage Unit Relationships

These show the unit math behind weight-based dosing. They are educational, not clinical guidance.

Total dose

dose = mg/kg × kg

A per-kilogram dose times body weight gives the total dose in milligrams.

mg → µg

× 1000

One milligram is 1,000 micrograms. Potent drugs are often dosed in µg.

kg ↔ lb

× 2.20462

Body weight often needs converting between kilograms and pounds before dosing.

How to Use the Dosage Converter

1
Identify the dose unit
Note whether the value is a rate (mg/kg, µg/kg) or a total amount (mg, µg), since they aren't interchangeable without a weight.
2
Enter the value
Type the figure you want to convert — a per-kilogram rate or a mass amount.
3
Choose 'from' and 'to' units
Select matching units (e.g. mg to µg), then swap if needed.
4
Verify with a professional
Use the converted units to understand the math — but confirm any actual dose against the drug label and a qualified prescriber.

Key Dosage Concepts

Weight-based dose (mg/kg)

A dose scaled to body weight, common in paediatrics. Multiply the per-kilogram rate by weight in kilograms to get the total dose.

Microgram dosing

Many potent drugs are dosed in micrograms (µg). A misplaced prefix (mg vs µg) is a 1,000-fold error — a serious patient-safety risk.

Maximum dose

Weight-based dosing is capped by a maximum total dose for larger patients. The unit math alone doesn't apply that ceiling.

Concentration matters too

Turning a dose in mg into a volume to administer needs the drug's concentration (mg/mL) — a separate, drug-specific step.

Real-World Dosage Unit Examples

👶

Paediatric dosing

A 15 mg/kg dose for a 20 kg child is 300 mg total. Children's medicines are very commonly weight-based.

💊

Microgram drugs

A 0.5 mg dose equals 500 µg. Confusing mg and µg for a potent drug is a classic, dangerous error.

⚖️

Weight conversion first

A 154 lb adult is 70 kg. Weight-based doses need the patient's weight in kilograms before the rate is applied.

📋

Checking a rate

Verifying that 5 mg/kg for a 70 kg patient is 350 mg total is the kind of unit check this tool supports.

🧪

Dose vs volume

A 250 mg dose of a 50 mg/mL solution is 5 mL. The mg-to-mL step needs the drug's concentration, not just unit conversion.

📚

Pharmacology study

Students use unit conversions to learn how rates, weights, and totals relate — without it being a prescribing aid.

Best Practices for Dosage Unit Conversion

✓Never use this tool to prescribe. It converts units only. Every real dose must come from a qualified prescriber, the drug label, and clinical protocols — not a unit converter.
✓Guard the mg/µg prefix. Milligrams and micrograms differ by 1,000. A prefix slip in dosing is among the most dangerous medication errors — double-check it.
✓Convert weight to kilograms first. Weight-based doses use kg. Convert a pound weight to kilograms before applying an mg/kg rate.
✓Apply maximum doses separately. Weight-based math can exceed a drug's maximum total dose in larger patients. The cap is a clinical rule, not a unit conversion.
✓Use concentration for volume. To find the volume to give, divide the dose (mg) by the concentration (mg/mL). That step is drug-specific and beyond unit conversion.

Common Dosage Unit Mistakes

Confusing mg and µg

A 1,000-fold prefix error between milligrams and micrograms is a well-documented and potentially fatal medication mistake.

Skipping the weight conversion

Applying an mg/kg rate to a weight in pounds, not kilograms, miscalculates the total dose by a factor of about 2.2.

Ignoring the maximum dose

Weight-based math can produce a total above the drug's ceiling for heavier patients. The cap must be applied separately.

Treating dose as volume

A dose in mg isn't a volume in mL. Converting requires the drug's concentration, which a unit tool doesn't supply.

Why Understanding Dosage Units Matters

Weight-based dosing and microgram-level drugs make medication math unforgiving: a misplaced prefix or a pound-versus-kilogram slip can change a dose by orders of magnitude, and dosing errors are a leading source of preventable harm in healthcare. Understanding the unit relationships — rate times weight, milligrams versus micrograms — is foundational to catching such errors.

This converter exists to teach and check that unit math, not to replace clinical judgement. Real prescribing depends on the drug's label, maximum doses, formulation, renal and hepatic function, and a qualified professional — none of which a unit converter captures. Use it to build understanding; always defer to a prescriber and authoritative references for any actual patient dose.

Built for healthcare and pharmacology students and professionals to understand and check dosage unit math — not a prescribing tool.

Linear unit factors follow the BIPM SI brochure, the NIST Guide to the SI, and ISO 80000. Currency rates load live from open.er-api.com; crypto prices from CoinGecko. See our methodology and editorial policy. Educational only — not certified for regulated trading, settlement, medical, or aerospace use.

Medical Dosage Converter FAQs

A weight-based dose is given as an amount per kilogram of body weight (mg/kg). Multiply that rate by the patient's weight in kilograms to get the total dose. For example, 15 mg/kg for a 20 kg child is 15 × 20 = 300 mg. This tool helps you understand and check that unit math, but real dosing must come from a qualified prescriber.

Multiply milligrams by 1,000 to get micrograms, since 1 mg = 1,000 µg. So 0.5 mg is 500 µg. This conversion is critical in medicine because many potent drugs are dosed in micrograms, and confusing mg with µg creates a 1,000-fold error that can cause serious harm.

No. This is an educational unit converter, not a prescribing or clinical decision tool. It does not account for maximum doses, drug concentrations, formulations, organ function, or clinical context. Any actual medication dose must be determined by a qualified prescriber using the drug's labelling and your institution's protocols.

Because weight-based doses are almost always expressed per kilogram (mg/kg). If a patient's weight is in pounds, you must convert it to kilograms first (divide by 2.20462) before applying the rate, or the total dose will be off by a factor of about 2.2 — a significant and dangerous error.

Divide the dose in milligrams by the medication's concentration in mg/mL to get the volume in millilitres. For example, a 250 mg dose of a 50 mg/mL solution is 250 ÷ 50 = 5 mL. This step needs the specific drug's concentration, which is why it goes beyond simple unit conversion and requires the product information.

The unit conversions themselves (mg to µg, kg to lb, and weight-based multiplication) are mathematically exact to your input precision. However, accuracy of any clinical dose depends on factors the tool does not handle — maximum doses, concentration, and clinical judgement — so it must never be used as a substitute for professional prescribing.