Dosage calculation for nursing students, step by step
Free calculators that show every step, unlimited practice problems with full corrections, and a timed practice exam. From tablets and IV drip rates to heparin and mcg/kg/min drips.
A free tool from MedTestBank.com, nursing test banks for your textbooks.
IV drip rate calculator
14 calculators, every step shown
Each calculator explains the formula, works through examples, lists the common mistakes and links to practice problems on the same topic.
Oral and injectable doses
- Tablet Dosage Calculator (Desired over Have)Calculate how many tablets or capsules to give with the desired over have formula, including g, mg and mcg conversions.
- Liquid Medication and Injection Dosage Calculator (mL)Calculate how many mL to give for oral liquids and injections with desired over have × quantity, and the right rounding for the syringe.
- Reconstitution Calculator for Powdered MedicationsCalculate the mL to withdraw after reconstituting a powdered medication, using the concentration printed on the label, and how many doses the vial holds.
IV infusions
- IV Flow Rate Calculator (mL/hr)Calculate the pump rate in mL/hr from the volume and the infusion time, with every step shown the way nursing programs teach it.
- IV Drip Rate Calculator (gtt/min)Calculate drops per minute for a gravity IV infusion from the volume, the time and the drop factor of the tubing, with each step explained.
- IV Infusion Time CalculatorFind how long an IV will take to infuse, and the time it will finish, from the volume and the rate in mL/hr.
Weight-based and pediatric
- Weight-Based Dosage Calculator (mg/kg)Calculate doses ordered in mg/kg, mcg/kg or units/kg, per dose or per day divided, with pounds to kilograms conversion and the volume to give.
- Pediatric Safe Dose Range CalculatorCheck whether a pediatric order is within the safe dose range in mg/kg/day or mg/kg/dose, the way you are asked to on nursing exams.
- Body Surface Area (BSA) Calculator and mg/m² DosingCalculate body surface area with the Mosteller formula and a dose ordered in mg/m², from height and weight in metric or US units.
Critical care drips
- mcg/kg/min to mL/hr Calculator (IV Drips)Convert a weight-based critical care infusion in mcg/kg/min, or a dose in mcg/min, to a pump rate in mL/hr, and back.
- Heparin Drip Calculator (units/hr to mL/hr)Calculate a heparin infusion rate in mL/hr from units/hr or a weight-based order in units/kg/hr, and the bolus dose in units.
- Insulin Drip Calculator (units/hr to mL/hr)Calculate the pump rate for an IV regular insulin infusion from units/hr or units/kg/hr, or find the units/hr infusing from the rate.
Conversions and solutions
- Nursing Unit Conversion CalculatorConvert the units used in medication math and patient care: g, mg and mcg; L and mL; pounds and kilograms; teaspoons, tablespoons and ounces; inches and cm; °F and °C.
- Percent and Ratio Solution Calculator (mg/mL)Convert solution strengths given as a percent (2% lidocaine, D5W, 50% magnesium sulfate) or a ratio (1:1,000) to mg/mL, and find how much drug is in a volume.
How to use it to pass med math
Learn the method
Read the formula and the worked examples, or the guides on dimensional analysis and desired over have.
Practice until it is automatic
Solve new problems on each topic, checked instantly with the full correction when you miss one.
Test yourself
Take the timed 20-question practice exam and review every correction.
Formulas and methods
Short guides to the methods nursing programs teach, with the rules that cost points on exams.
- Dosage Calculation Formulas: Nursing Cheat SheetEvery formula you need for nursing dosage calculation exams on one page: tablets, liquids, IV rates, drip rates, weight-based doses, critical care drips, BSA and conversions.
- Dimensional Analysis for Nursing Dosage CalculationLearn dimensional analysis, the one-line method that solves every dosage calculation by cancelling units, with worked nursing examples.
- Desired over Have Formula (D/H × Q)The desired over have formula (D ÷ H × Q), also called the formula method, explained with tablet, liquid and injection examples.
- Ratio and Proportion Method for Dosage CalculationSolve dosage problems by setting up two equal ratios and cross-multiplying, with nursing examples for tablets, liquids and injections.
- Rounding Rules for Nursing Dosage CalculationWhen and how to round in nursing dosage calculation: tablets, mL, drops per minute, mL/hr, weights and BSA, plus leading and trailing zero rules.
- Nursing Conversion Chart: Metric, Household and TemperatureThe conversion factors used in nursing math in one chart: metric mass and volume, household measures, weight, length and temperature.
- Medication Abbreviations: Do Not Use List and Safe AlternativesThe Joint Commission's official Do Not Use list, other error-prone abbreviations flagged by ISMP, and the common abbreviations you will see in medication orders.
- IV Drop Factors: Macrodrip vs Microdrip TubingWhat the drop factor is, how macrodrip and microdrip tubing differ, when each is used, and how the drop factor enters the drip rate formula.
Ready for real exam questions?
MedTestBank.com has test banks for the textbooks nursing programs use: pharmacology, fundamentals, medical-surgical, pediatrics, maternity and more.
Questions about dosage calculation
What is dosage calculation in nursing?
It is the math nurses use to give the right amount of medication: tablets and mL from the order and the label, IV rates in mL/hr and gtt/min, weight-based and pediatric doses, and critical care drips. Most nursing programs require a med math exam with a passing score of 90 to 100%.
Which method should I use: dimensional analysis or desired over have?
Both give the same answer. Use the method your program teaches. Desired over have is quick for single-step doses; dimensional analysis keeps multi-step problems, like IV drips and mcg/kg/min, in one line.
Are these calculators enough to pass my dosage calculation exam?
They show every step so you can learn the method, and the practice problems and the timed practice exam let you test yourself. On the exam you will need to do the math yourself, with your program's rounding rules.