Education only. Follow facility policy, pharmacy labeling, the prescribed concentration, and smart-pump requirements. Read the educational notice.
What this calculator is for (what it is not)
For: school med-math exams, skills lab practice, and building muscle memory for dimensional analysis on continuous infusions.
Not for: overriding a smart pump, inventing a concentration, or replacing pharmacy / facility policy. If your order, bag label, and pump library disagree, escalate per your program or unit rules; do not "force" a student-calculator answer onto a live patient.
Information to gather and the formula
This page provides a static formula and worked example. Write down the following information before solving a practice problem.
| Input | Units | Notes |
|---|---|---|
| Patient weight | kg | Convert from lb if needed using your program's conversion rule |
| Prescribed dose | mcg/kg/min | Weight-based continuous rate |
| Drug amount in bag | mg | Use the labeled infusion bag, not vial strength |
| Total bag volume | mL | Use the volume stated in the practice problem |
| Rounding | Decimal places | Follow your program's instructions; round at the end |
Rate (mL/hr) = [weight (kg) × dose (mcg/kg/min) × 60 min/hr] ÷ concentration (mcg/mL)
Concentration (mcg/mL) = [drug amount (mg) × 1,000 mcg/mg] ÷ volume (mL)The worked example uses the public homepage values: 70 kg, 5 mcg/kg/min, and 400 mg in 250 mL.
Formula block: cancel units left to right
Write the setup so each unit cancels:
- kg in the numerator cancels the "per kg" in mcg/kg/min
- mcg in the numerator cancels mcg in the concentration denominator
- min cancels with the 60 min/hr conversion
- You should be left with mL/hr
If anything else remains (mg, lb, mL/min), stop and fix the setup before you trust the arithmetic.
Worked example: dopamine 5 mcg/kg/min (homepage numbers)
Order: dopamine 5 mcg/kg/min IV; patient weighs 70 kg.
Available: dopamine 400 mg in 250 mL D5W.
Find: mL/hr.
Step 1: Dose per minute
70 kg × 5 mcg/kg/min = 350 mcg/min
Units check: kg cancels → mcg/min.
Step 2: Concentration
400 mg ÷ 250 mL = 1.6 mg/mL
1.6 mg/mL × 1000 mcg/mg = 1,600 mcg/mL
Units check: mg cancels with mcg/mg → mcg/mL. Do not mix mg/mL in the denominator against mcg/min in the numerator without this conversion.
Step 3: Pump rate
350 mcg/min ÷ 1,600 mcg/mL × 60 min/hr = 13.125 mL/hr
Rounded to one decimal: 13.1 mL/hr
Education only. Follow facility policy, pharmacy labeling, the prescribed concentration, and smart-pump requirements. Read the educational notice.
Why students miss mcg/kg/min problems
- Forgetting × 60: answer left in mL/min instead of mL/hr
- mg vs mcg mismatch: using 1.6 mg/mL against 350 mcg/min without ×1000
- Weight in lb: skipping ÷ 2.2 (or the conversion specified by your program)
- Rounding the concentration early: then compounding error into the final rate
- Wrong bag: calculating from vial strength instead of the diluted infusion bag on the label
- Trailing zeros / missing leading zeros when writing related push doses elsewhere on the same exam (ISMP-style formatting)
A good mcg/kg/min dimensional analysis habit is to refuse to proceed until every intermediate line has a unit label.
Related IV math (different formula)
Volume-over-time pump rates and manual drip rates (gtt/min) are a different path; no mcg/kg/min concentration step. Use the IV flow rate calculator for those. For the broader dosage-calculation hub (oral, push, drips, study tips), see Dosage calculation.
How to practice mcg/kg/min without a live pump
- Copy the three-line template (dose/min → concentration → mL/hr) onto paper.
- Change one variable at a time (weight, dose, or bag strength) and predict whether mL/hr should rise or fall before you calculate.
- Match your program's rounding rule (often one decimal for pumps).
- When you miss, highlight the first line where units failed, not just the final number.
- Move into OmniRN's dose solver when you want more volume with the same visible-proof style.
Practice in OmniRN
OmniRN's dose solver shows dimensional-analysis steps beside 2,151+ practice questions with rationales for every option and 1,178 FSRS flashcards. The 765+ NGN figure is a separate content scope. Explore the six-module, 23-topic curriculum.
| Plan | Price | Billing |
|---|---|---|
| Monthly plan | $9.99/month | 3-day trial for first-time subscribers; payment method required. Renews monthly. |
| Annual plan | $79.99/year | 3-day trial for first-time subscribers; payment method required. Renews annually. |
| Lifetime access | $149.99 one time | One payment; no trial or renewal. |
For monthly and annual plans, cancel before the trial ends to avoid the first charge. Cancel anytime online. See subscription terms and billing help.
Study plan: one week of drip confidence
Day 1-2: Volume → mL/hr only (IV flow rate guide) so pump-time math feels automatic.
Day 3-4: Desired/have oral and IV push with ISMP-style decimal formatting.
Day 5-6: mcg/kg/min with the dopamine template above; vary weight and dose.
Day 7: Mixed set under timed conditions matching your school's calculator rules (some programs allow four-function calculators only).
If your exam is pass/fail at a high cut score, prioritize setup accuracy over speed until your error rate drops. Speed follows clean unit cancels.
FAQ
Is this the same as a heparin protocol calculator?
Heparin and other protocols often add nomograms, aPTT targets, and facility-specific tables. This page teaches the generic mcg/kg/min → mL/hr dimensional-analysis path. Always use your facility protocol when one exists.
Can I use lb instead of kg?
Convert to kg first (commonly ÷ 2.2 in nursing math courses). Entering lb as if it were kg will inflate the rate and is a classic exam trap.
Does OmniRN replace my school's required method?
No. If your instructors require ratio-proportion on scratch paper, practice that form too. OmniRN emphasizes visible dimensional analysis because unit cancels are where most points disappear.
Can I enter my own values here?
This page contains a static worked example and formulas. There is no interactive input widget.
Is there a 3-day trial?
Monthly and annual plans include a 3-day trial for first-time subscribers, with a payment method required at checkout. Cancel before the trial ends to avoid the first charge.
Continue studying
Work the dopamine example on paper, then continue drip practice in OmniRN with a 3-day trial for first-time subscribers (card required) on monthly/annual plans, or choose lifetime at $149.99.
Related guides: Dosage calculation hub · IV flow rate calculator · Flashcards · Bowtie questions
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Sources
Sources checked September 30, 2026.