Medication Dosage Calculator
Calculate the volume to administer using the D/H × V formula or concentration method. Built for EMT and paramedic exam prep.
Part of the EMS Medical Calculator Suite
Common EMS drug presets
The amount in the unit you're measuring — e.g. 1 mg per vial
mL in the container that holds the Dose on Hand
Common EMS Drug Concentrations
| Drug | Concentration | Common EMS dose |
|---|---|---|
| Epinephrine 1:1,000 | 1 mg/mL | 0.3 mg IM (adult anaphylaxis) |
| Epinephrine 1:10,000 | 0.1 mg/mL | 1 mg IV (adult cardiac arrest) |
| Naloxone (Narcan) | 0.4 mg/mL | 0.4–2 mg IV/IM/IN |
| Dextrose 50% | 0.5 g/mL | 25 g IV (12.5–25 g depending on protocol) |
| Atropine | 0.1 mg/mL | 0.5–1 mg IV for bradycardia |
| Adenosine | 3 mg/mL | 6 mg rapid IV push (PSVT) |
| Morphine | 10 mg/mL | 2–4 mg IV titrated |
| Midazolam (Versed) | 5 mg/mL | 5–10 mg IM for seizure |
Drug concentrations and doses vary by jurisdiction. Always follow your local EMS protocols and medical director's standing orders.
How the Medication Dosage Formula Works
The standard EMS dosage formula — sometimes called D/H × V — answers the question: "How many milliliters do I draw up to give the ordered dose?" It requires three values:
- D (Desired): the dose your medical direction has ordered
- H (Have / On Hand): the dose contained in the vial
- V (Volume): the volume of liquid that contains H
Example: You need to give 0.5 mg of drug X. Your vial is labeled "2 mg/5 mL." So H = 2 mg, V = 5 mL, D = 0.5 mg. Volume = (0.5 ÷ 2) × 5 = 1.25 mL.
The concentration method is a shortcut: if the label already tells you the drug per mL (e.g., "1 mg/mL"), divide the ordered dose by that number directly. The result is the same.
Frequently Asked Questions
What does 1:1,000 mean on an epinephrine vial?
Epinephrine 1:1,000 means 1 gram per 1,000 mL, which equals 1 mg/mL. Epinephrine 1:10,000 means 1 gram per 10,000 mL = 0.1 mg/mL. The ratio notation tells you the concentration — never assume; always read the label.
Why does my calculation give a very large volume?
A large calculated volume almost always means a unit mismatch. Check that your "Desired" and "Dose on Hand" are in the same units. Common errors: ordering in mg but entering the vial in mcg (1,000× difference), or confusing g and mg.
How do I convert mcg to mg for a calculation?
Divide micrograms by 1,000 to get milligrams. 500 mcg = 0.5 mg. For the calculation to work correctly, both Desired and Have must be in the same unit. If your label is in mg and your order is in mcg (or vice versa), convert first. For weight-based mcg/kg/min drips, use the weight-based dose calculator.
Is this calculator tested on the NREMT?
Yes. Medication dosage calculations appear on the NREMT cognitive exam. You won't have access to a calculator — practice solving problems manually using scratch paper. Use this tool to verify your answers, not to bypass the thinking process.
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