Pediatric Dose Calculator

Enter weight, height, age, and medicine strength below. See single-dose, daily totals, and volume instantly. Use built-in checks to avoid dosing mistakes every time.

Dose visualization

Plotly graph

This chart summarizes the calculated dose, daily total, and estimated volume per dose.

Calculate a result to render the chart.

Why weight matters in pediatric dosing

Many pediatric references express dosing as mg/kg because drug exposure often correlates with body mass. When weight changes rapidly, recalculating each visit reduces error. This calculator multiplies the selected mg/kg by weight in kilograms to produce a single-dose amount, then projects a daily total using doses per day.

When BSA-based dosing is preferred

Some therapies, including several oncology and specialty protocols, use mg/m2 because surface area can better reflect metabolic capacity in certain settings. The Mosteller method estimates BSA as the square root of (height in cm times weight in kg divided by 3600). The dose is then mg/m2 times BSA, which can be useful when dosing guidance is written in BSA terms.

Turning milligrams into measurable volume

Liquid formulations often require an mL instruction. The calculator converts mg to mL by dividing the final single dose by the product strength in mg/mL. For example, a 180 mg dose with a 25 mg/mL suspension yields 7.2 mL. Always confirm the concentration on the specific label you have, and use an appropriate oral syringe for accuracy.

Classic rules: where they help and where they do not

Clark’s, Young’s, and Fried’s rules estimate a child dose as a fraction of an adult dose using weight in pounds, age in years, or age in months. These are screening tools, not prescribing standards. They can highlight whether an order is far outside an expected range, but they do not replace protocol-based dosing, renal adjustments, or indication-specific guidance.

Dose caps and daily limits for safer planning

Many medicines define a maximum single dose and a maximum daily dose. If you enter a max single dose, this tool caps the calculated single dose and reports that a cap was applied. If the computed daily total exceeds the max daily value, the calculator flags a warning so you can reassess the plan and re-check frequency.

Documentation and handoff-friendly outputs

Clear documentation supports safer handoffs. CSV export captures each input and computed field for quick review, while the PDF summary provides a printable record of the method, concentration, and totals. Use exports to double-check arithmetic, confirm units, and communicate calculations during team review, especially when multiple clinicians verify the same order independently.

FAQs

1) What inputs are required for a calculation?

You need weight, doses per day, and concentration. Add mg/kg for weight-based, height plus mg/m2 for BSA, or an adult dose for rule-based estimates.

2) Does the calculator automatically cap doses?

If you enter a max single dose, the tool caps the single dose and notes it. Max daily dose is not forced; it triggers a warning so you can reassess.

3) Which method should I choose: mg/kg or mg/m2?

Use the method specified by your dosing reference. Many common medicines use mg/kg, while some specialty protocols use mg/m2. Do not switch methods without guidance.

4) How is volume per dose calculated?

Volume equals the final single dose in mg divided by the medicine concentration in mg/mL. Verify the label strength, especially when multiple strengths exist.

5) Are Clark’s, Young’s, and Fried’s rules accurate?

They are rough screening estimates based on adult dose fractions. They can help detect outliers, but they are not a substitute for protocol dosing, adjustments, or clinical judgment.

6) Can I use the exports for charting or records?

Yes. CSV is easy to import into spreadsheets for audits, and PDF is useful for printing. Treat exports as calculation notes, not medication orders.

Calculator
Results appear above after you calculate.
White theme
Choose a method aligned with your reference.
Shown in the output and downloads.
Example: q8h = 3/day, q12h = 2/day.
Used in mg/kg and BSA modes.
Needed for BSA mode (Mosteller).
Used to convert mg → mL.
Single-dose mg/kg value.
Single-dose mg/m2 value.
Reference adult single dose.
For rough estimates only.
Used by Young's rule if given.
Used by Fried's rule if given.
If exceeded, single dose is capped.
If exceeded, you’ll get a warning.

Example data table

Scenario Weight (kg) Height (cm) Method Input dose Freq/day Concentration Output (single mg) Output (mL)
Otitis media, oral suspension 18 110 mg/kg 10 mg/kg 3 25 mg/mL 180 mg 7.20 mL
Oncology protocol, infusion dose 28 128 mg/m2 250 mg/m2 1 10 mg/mL ≈ 220 mg ≈ 22.0 mL
Rule estimate, quick screening 22 120 Clark’s rule Adult 500 mg 2 50 mg/mL ≈ 161 mg ≈ 3.22 mL

Values are illustrative only and should not be used as prescriptions.

Formula used

  • Weight-based: Single dose (mg) = Dose (mg/kg) × Weight (kg)
  • BSA-based (Mosteller): BSA (m2) = √[(Height(cm) × Weight(kg)) ÷ 3600]
  • BSA dose: Single dose (mg) = Dose (mg/m2) × BSA (m2)
  • Clark’s rule: Child dose = Adult dose × (Weight(lb) ÷ 150)
  • Young’s rule: Child dose = Adult dose × (Age ÷ (Age + 12))
  • Fried’s rule: Infant dose = Adult dose × (Age months ÷ 150)
  • Daily total: Daily (mg/day) = Final single dose (mg) × Doses per day
  • Volume conversion: mL per dose = Final single dose (mg) ÷ Concentration (mg/mL)

How to use this calculator

  1. Pick a calculation mode that matches your dosing reference.
  2. Enter weight and concentration, then add height for BSA.
  3. Provide mg/kg, mg/m2, or an adult dose for rules.
  4. Set doses per day, and optionally enter maximum limits.
  5. Press Calculate to show results above the form.
  6. Use the download buttons to export your calculation record.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.