Drug calculations in your head or calculator?

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I'm starting my ABSN program next month and just learned that we have a drug calc quiz on the first day (yikes!). Anyway, I started reviewing basic drug calcs and the book I'm using writes everything out long hand. At your school, are you required to do your drug calcs in your head or can you use a calculator? I'm terrible at math in my head.

I do all of my drug calculations in my head and on a piece of paper while on the floor.

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Wow...how can you have a quiz the 1st day? That's crazy! Anyway, we're required to buy this $12 calculator from the bookstore and we're only allowed to use that. I would never feel confident doing it in my head, that's when accidents can happen, IMO.

Using a calculator instead of knowing and understanding the math enough to do it in your head and/or on paper is when accidents happen, IMHO. ;)

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hummm... this is how I go about it... I set up the calculation on paper (usually ratio and proportion) and get it down to something like 246x=1184. Now I know how to solve that, but dividing 1184 by 246 in my head or on paper gives me A LOT of room for error. At this point it's where I let the calculator step in. I don't think I would trust myself using ONLY a calculator and not setting up the problem on paper first, but I also know I wouldn't trust myself doing the whole equation on paper without a calculator either. I use a $4 Target calculator. Very basic. It's all you need.

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I was speaking for myself lol. I also said it is very possible to do, anything is possible. You don't inherit math skills, you have to find a way to learn it. I know it is possible because when I was young I used to be so dumb at math and I was forced to learn it and now I am good at it. By the way don't freak out because the dosage calculations are easy and simple-- and you are going to learn it. It takes a little practice. It's not calculus 2 or 3.

My husband is also a whiz when it comes to math in his head...drives me crazy! I asked him to teach me, but a teacher he's not. lol And thank goodness it's not calculus 2 or 3...or 1! I'd be sunk. :)

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Specializes in Pediatric Critical Care.

My school we are NOT permitted the use of the calculator we have to do it all in our head

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Specializes in Med Surg.
Actually, I think it's to the patient's benefit for me to use a calculator...

Here's one of the problems I was looking at today: 42 x 1/9450 x 3/0.02. Now I know this isn't rocket science, but I certainly cannot do that in my head. Long-hand written out on paper, sure, but math is not my strong suit and the room for error seems a little too high (especially for me).

What are you calculating with this problem? What's the drug and how much are you giving? Maybe we're talking about two different things.

We're not allowed to use calculators for drug calc problems and I'm really glad that they made us work them out. I think it gives us an advantage. Yes, out in the real world we'll be able to use calculators, but there's no reason a nurse can't work out a drip rate or a safe peds dose with a piece of paper.

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What are you calculating with this problem? What's the drug and how much are you giving?

Nothing in particular. It was just a sample problem from the intro chapter of my medical dosage book. It wasn't in regards to any drug, just an intro to get us back used to multiplying and dividing fractions/decimals (something I haven't really done since about 5th grade!).

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Using a calculator instead of knowing and understanding the math enough to do it in your head and/or on paper is when accidents happen, IMHO. ;)

Calculators don't make mistakes. Someone doing it in their head can. If you do BOTH then that's another story....I think that's acceptable but I wouldn't feel comfortable taking that chance.

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Using a calculator instead of knowing and understanding the math enough to do it in your head and/or on paper is when accidents happen, IMHO. ;)

I don't understand this comment as you have to understand and know it to be able to punch in the correct numbers. In other words, you would have to know how to solve for gtts/min before you could just punch in numbers on a calculator. Yes, errors can happen on calculators too if not careful.

As a patient, I would want and prefer my nurse to use a calculator or at least double check their math with one.

There are way too many med errors in the world and isn't that why we have the six rights and we should double check our math. Why does NCLEX allow calculator use if the math is so easy....it is another check to keep the patient safe. I don't care how polished your math skills are and what level math you completed....anyone can make a silly mathematical error at any time.

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Landing a job as a pharmacy tech was the best thing i could have ever done to learn med math!!

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My school we are NOT permitted the use of the calculator we have to do it all in our head

Solving in your head is (6 X 7 and you say 42).

You are not allowed to write out the problem and solve? Are you saying like patient needs 50 mg of med and the bottle is 25 mg/tablet. You select A,B,C,D and one answer is I will give two tablets. Yes, you can do this in your head very quickly.

Pt. needs 150mL of D5W in 1 hr. The drop factor is 15 gtt/mL. You then pick a ABCD answer and solve this in your head as well?

I find this odd they would not let you write out the equation/problem and solve it?

gtt/min = 150mL/60 X 15gtt/mL I see many med errors occuring if this is computed in our head only and you would have to round correctly. Yes, I could come up with the problem in my head and say 150/4 but I would still want to write it out to make sure I calculate it correctly on paper.

IMO, this is where med errors will happen. I wasn't allowed a calculator on the nurse entrance exam, but you got to use scratch paper and that didn't involve meds for people.

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Yes, we are allowed to use a calculator on exams, and we are allowed to use them in clinicals. I am not great in math in my head, I know the formulas, how to do the calculations, but I am definitely more comfortable using a calculator. We had a basic math exam on the first day of class, no drug calculations, but multiplying decimals, fractions, etc. We were not allowed a calculator on that exam.

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