What goes on a dosage calculation cheat sheet?

The formulas for doses, pump rates, drip rates and infusion times; the metric and household equivalents; the drop factors of IV tubing; and the rounding rules. When you study, use your program's rounding rule and notation; those are the ones graded.

What is a med math cheat sheet?

A one-page reference for medication math: the formulas, conversion factors, drop factors and rounding rules used in dosage calculation. It summarizes; the guides this sheet links show how to set each problem up and work it through.

Which conversions do nurses need to memorize?

Open RN's must-memorize list includes 1 g = 1,000 mg, 1 mg = 1,000 mcg, 1 kg = 1,000 g, 1 kg = 2.2 lb, 1 L = 1,000 mL, 1 tsp = 5 mL, 1 tbsp = 15 mL and 1 fl oz = 30 mL; rate problems add 1 hr = 60 min.

Can you use a cheat sheet on a dosage calculation exam?

Only if your program allows it; its syllabus or exam policy says what you may bring. This sheet is for studying: to learn the formulas and factors, and to check your setup while you practice.

How do you round in dosage calculations?

Usually once, at the final answer; Mercer County rounds a converted weight first. Published rules often round an adult dose over 1 mL to the tenth, a dose under 1 mL to the hundredth and drip rates to a whole drop; pump rates vary. Your syllabus's rule is graded.

Methods and notations · Published by Maksym Shevchuk · Updated 2026-11-03

Dosage calculation cheat sheet: nursing math on one printable page

Short answer

This sheet puts the nursing math of dosage calculation on one printable page: the formulas, such as D ÷ H × Q for doses, mL ÷ hr for pump rates and mL × drop factor ÷ min for drip rates; the metric and household equivalents; IV drop factors; and published rounding rules. Your program's rounding rule is the one graded.

Formulas

Each row is one kind of problem, and any notation your program teaches gives the same answer. Write a unit with every number: in dimensional analysis the units you are getting rid of cancel on the diagonal, so a factor set upside down shows as a unit that does not cancel. The formulas guide explains each row, and the desired over have guide explains D ÷ H × Q, including an order and a label in different units.

Formulas by kind of problem. D is the dose desired (the order), H the dose on hand (the label) and Q the quantity H comes in; put D and H in the same unit before you divide.
Problem	Formula	Answer in
Tablets and capsules	D ÷ H × Q, where Q is one tablet or capsule	tablets or capsules
Oral liquids	D ÷ H × Q, where Q is the volume the label's strength refers to, such as 5 mL	mL
Injections	D ÷ H × Q, where H and Q come from the vial's concentration	mL
Reconstitution	D ÷ the concentration after mixing, from the label, × the volume that concentration refers to	mL
Unit conversions	amount × a factor with the unit you are leaving on the bottom	the new unit
mL per hour	volume (mL) ÷ time (hr)	mL/hr
mL per hour from a dose per hour	dose per hour ÷ dose in each mL	mL/hr
mL per hour from a dose per minute	dose per minute × 60 ÷ dose in each mL, in the same drug unit	mL/hr
mL per hour from a dose per kg per minute	dose per kg per minute × weight (kg) × 60 ÷ dose in each mL, in the same drug unit	mL/hr
Drops per minute	volume (mL) × drop factor (gtt/mL) ÷ time (min)	gtt/min
Drops per minute from mL/hr	mL/hr × drop factor ÷ 60	gtt/min
Infusion time	volume (mL) ÷ rate (mL/hr)	hr
Weight-based dose	dose per kg × weight (kg), with kg = lb ÷ 2.2	the order's unit, such as mg

Conversions

Open RN lists these metric and household equivalents among the ones nurses must memorize; rate problems add hours to minutes. Going to a smaller unit gives a bigger number. The conversion chart lists each direction, with worked examples.

Conversion factors: multiply by the one with the unit you are leaving on the bottom, turned over to go the other way
Equivalent	Multiply by
1 g = 1,000 mg	1,000 mg / 1 g or 1 g / 1,000 mg
1 mg = 1,000 mcg	1,000 mcg / 1 mg or 1 mg / 1,000 mcg
1 kg = 1,000 g	1,000 g / 1 kg or 1 kg / 1,000 g
1 kg = 2.2 lb	1 kg / 2.2 lb or 2.2 lb / 1 kg
1 L = 1,000 mL	1,000 mL / 1 L or 1 L / 1,000 mL
1 tsp = 5 mL	5 mL / 1 tsp
1 tbsp = 15 mL	15 mL / 1 tbsp
1 fl oz = 30 mL	30 mL / 1 fl oz or 1 fl oz / 30 mL
1 hr = 60 min	60 min / 1 hr or 1 hr / 60 min

IV drop factors

The drop factor is the number of drops in 1 mL through a gravity tubing set, and an exam problem gives it. From a rate in mL/hr, drops per minute are mL/hr × drop factor ÷ 60, which the last column works out for each factor; drops are rounded to a whole number. The IV drip rate guide explains both drip rate formulas.

Drop factors as Open RN lists them; the one in use is printed on the tubing package
Drop factor	Tubing	Drops per minute from mL/hr
10 gtt/mL	Macrodrip	mL/hr ÷ 6
12 gtt/mL	Macrodrip	mL/hr ÷ 5
15 gtt/mL	Macrodrip	mL/hr ÷ 4
20 gtt/mL	Macrodrip	mL/hr ÷ 3
60 gtt/mL	Microdrip	The same number as mL/hr

Rounding rules

Most published rules round once, at the final answer; Mercer County rounds a weight converted to kilograms to the tenth first. The rounding rules guide sets the published rules side by side, and the leading and trailing zeros guide covers how to write the answer. DoseReady's practice problems are rounded once, at the end: nearest tenth, half rounds up, except tablets and capsules, rates in milliliters per hour and drip rates in drops per minute, which go to the nearest whole number, half rounds up.

Rounding rules as published sources state them, read on 2026-11-03. Where your syllabus differs, its rule is the one graded.
Answer	Published rule
When to round	At the final answer (Open RN, Shawnee State; WisTech: avoid rounding intermediate calculations). Mercer County converts a weight in pounds to kilograms first, rounded to the tenth.
A dose over 1 mL	Nearest tenth (Open RN, adult oral liquids; Shawnee State, any final answer greater than one)
A dose under 1 mL	Nearest hundredth (Open RN, oral liquids; Shawnee State, any final answer less than one)
Drip rate (gtt/min)	Nearest whole number (Open RN, Bergen, Shawnee State); Mercer County reports manual drip rates in whole numbers
Pump rate (mL/hr)	Your program's rule: Mercer County allows the nearest tenth; WisTech's worked example asks for the nearest whole number; Open RN's multi-step example rounds to the hundredth, depending on agency policy and pump settings
Exactly half	Rounds up: “Five and up, round up” (Mercer County); Open RN rounds 0.05 and above up when rounding an adult oral liquid to the tenth
Writing the answer	A leading zero before a decimal point (0.5 mg) and no trailing zero after a whole number (1 mg), as ISMP lists them; a unit on every answer (Shawnee State, Mercer County)

Printing the sheet

Your browser's Print command prints this page as one sheet: the four tables and a line saying where they came from, without the site's menus, the explanations, the questions or the sources. Save it as a PDF the same way.

It is a study sheet; what you may bring into an exam is your program's rule. To test yourself, the printable practice test has 45 problems with an answer key, and the practice pages work each problem step by step.

Practice this

Dosage calculation practice problems with answers

Each problem opens to its worked solution, the answer under a stated rounding rule and the sources it is built from.

Questions

What goes on a dosage calculation cheat sheet?: The formulas for doses, pump rates, drip rates and infusion times; the metric and household equivalents; the drop factors of IV tubing; and the rounding rules. When you study, use your program's rounding rule and notation; those are the ones graded.
What is a med math cheat sheet?: A one-page reference for medication math: the formulas, conversion factors, drop factors and rounding rules used in dosage calculation. It summarizes; the guides this sheet links show how to set each problem up and work it through.
Which conversions do nurses need to memorize?: Open RN's must-memorize list includes 1 g = 1,000 mg, 1 mg = 1,000 mcg, 1 kg = 1,000 g, 1 kg = 2.2 lb, 1 L = 1,000 mL, 1 tsp = 5 mL, 1 tbsp = 15 mL and 1 fl oz = 30 mL; rate problems add 1 hr = 60 min.
Can you use a cheat sheet on a dosage calculation exam?: Only if your program allows it; its syllabus or exam policy says what you may bring. This sheet is for studying: to learn the formulas and factors, and to check your setup while you practice.
How do you round in dosage calculations?: Usually once, at the final answer; Mercer County rounds a converted weight first. Published rules often round an adult dose over 1 mL to the tenth, a dose under 1 mL to the hundredth and drip rates to a whole drop; pump rates vary. Your syllabus's rule is graded.

Sources

[1]Toney-Butler TJ, Nicolas S, Wilcox L. Dose Calculation Desired Over Have Formula Method. StatPearls (2023)ncbi.nlm.nih.gov
[2]Open RN, Nursing Skills 2e, 5.6 Using Dimensional Analysis (WisTech Open, 2023)wtcs.pressbooks.pub
[3]Open RN, Nursing Skills 2e, 5.4 Equivalencies (WisTech Open, 2023)wtcs.pressbooks.pub
[4]Open RN, Nursing Skills 2e, 5.5 Rounding (WisTech Open, 2023)wtcs.pressbooks.pub
[5]Open RN, Nursing Skills 2e, 5.17 Multi-Step Calculations (WisTech Open, 2023)wtcs.pressbooks.pub
[6]Open RN, Nursing Skills 2e, chapter 5, section 10: Reconstituted Medication (WisTech Open, 2023)wtcs.pressbooks.pub
[7]Open RN, Nursing Skills 2e, 5.11 Weight-Based Calculations (WisTech Open, 2023)wtcs.pressbooks.pub
[8]Open RN, Nursing Skills 2e, 5.14 IV Infusion by Gravity (WisTech Open, 2023)wtcs.pressbooks.pub
[9]Open RN, Nursing Skills 2e, 5.15 IV Infusion by Pump (WisTech Open, 2023)wtcs.pressbooks.pub
[10]Open RN, Nursing Skills 2e, 5.16 IV Completion Time (WisTech Open, 2023)wtcs.pressbooks.pub
[11]WisTech Open, Nursing Dosage Calculations, 4.1 Introduction to IV Flow Rates and Infusion Time (2024)wtcs.pressbooks.pub
[12]Bergen Community College Nursing, Pharmacological Math Computation Skills Self Learning Module (2023)bergen.edu
[13]Shawnee State University School of Nursing, Student Handbook 2026-2027, Math Policyshawnee.edu
[14]Mercer County Community College Nursing, Medication Calculation Guidelines (updated September 2020)mccc.edu
[15]ISMP, List of Error-Prone Abbreviations, Symbols, and Dose Designations (2024)online.ecri.org

No licensed clinician has reviewed this guide. How the guides are made. Exam practice, never for patient care. Follow your program's rules.