Select Page

Welcome back, my friend!

If you’re like me, you want to run away fast and far when your nursing professor mentions your upcoming dose calc test, huh? I figured, because we’re so much alike, you and I.

We would rather be searching cute DIY projects on Pinterest, cleaning the house, or meeting a friend for margaritas (ain’t no one got time for that anymore, am I right?!).

But I’ve got good news for you, girlfriend!

This little technique called dimensional analysis is your ticket to reclaiming your life back. Once you learn what I’m going to teach you today, you will be sailing through dosage calculations like it’s nothin’!

Why Dimensional Analysis is the Bee’s Knees

Dimensional Analysis, also know as stoichiometry or the railroad method, is the only technique I recommend when solving dosage calculation equations in nursing school. I love dimensional analysis for 4 main reasons:

1. It’s ridiculously simple to set-up
2. It makes it super easy to actually do the calculations
3. It works with just about every dose calc problem imaginable
4. It is pretty full proof that you’ll come up with the right answer
5. Keeps me from crying in a corner every time I hear the words “dose calc”

Are you convinced yet? I hope so! Because this will be your new secret nursing school weapon!

Be prepared to win the day, and then go celebrate with that margarita.

If you need to brush up on your dosage calculation conversions, be sure to download your FREE printable Dose Calc Conversion Cheat Sheet. Just submit your name and email below for exclusive access. 

Basic Dimensional Analysis Set Up

Last month we talked about the basic set up of dimensional analysis and the steps to follow to get it right every time. You can check out that blog post here.

Make sure not to skip or rearrange the steps, as it may lead you to the wrong answer. 

Following the steps listed in that blog post, your dimensional analysis should look like this:

Dimensional Analysis Blog Set Up

Let’s use the following example:

The doctor ordered 50mg of Metoprolol twice a day for hypertension. You only have 25mg tablets in the med cart. How many tablets will you give your patient?

Step 1: What do you need?

The question is asking for the number of tablets you will give the patient. This goes in the right hand side of your paper.

Dimensional Analysis Blog Set Up (1)

Step 2: What is your order?

For this question, the order is 50mg twice a day. This goes in the very left hand side of your paper.

Dimensional Analysis Blog Set Up Step 2

Step 3: What conversions do you need?

The question says that you have 25mg in each tablet available. This conversion goes in the middle of the paper.

Dimensional Analysis Blog Set Up Step 3

Did you get your FREE printable conversion cheat sheet yet? Now’s the time to do that by simply submitting your name and email below. 


Step 4: Solve the problem

This is were dimensional analysis starts to really come in handy!

All you need to do is make sure your units are on opposite sides of the “railroad” or fraction, multiply the entire top row, multiply the entire bottom row, and divide those two numbers. Instant magic!

Dimensional Analysis Blog Set Up Step 4

Step 5: Write the answer appropriately

Since our example problem doesn’t have a decimal, we don’t need to add or subtract any zeros or use rounding rules. Easy peasy!

If you have a dosage calculation problem that does require rules regarding zeros, remember: Nurse are LEADERS, not FOLLOWERS. This means that you include a leading zero, but never a trailing zero.

Click here to see why.

Step 6: Check your answer

Always, always, always double check your work. Many-a-time has my booty been epically saved by this step right here. Please do not skip it!

And there you have it! The simplest way to ace your dose calc problems every time, whether in real life or on an exam.

Comment below and tell me what your favorite margarita flavor is (or tea, if you prefer). Personally, I don’t think you can ever go wrong with strawberry anything. 🙂