Nursing medication math calculation – wv percentages made easy!

g'day welcome to tech mouth channel this video is a continuation of a series I've been making for our nurses looking at drug calculations and what this one is looking at specifically its percentages used in drug calculations now these percentages usually use to show the concentration of a particular active ingredient in a drug so what do I mean by that that's where you have say something like this 10% and you'll see quite often WV written after it now with this I'm going to show you first off just what this means and then how we can use this to work out a few things this various concentration based questions that you might come across or things like that now first off what does this mean when you see this this 10 % WV is fairly simple as long as you break it down 10% first off you're probably a well aware 10% means 10 out of 100 percentage is out of 100 the WV / tells us that we are the what the 10 and 100 mean okay what I mean by this you know 10 watts out of 100 watts the W stands for weight the weight specifically here is in grams this is 10 grams out of 100 this is where the V part comes in the V stands and volume the volume is given in mil okay this is 10 grams per hundred mil and that's pretty much what these mean so say for instance if you had it it was I I won't give you a different one here so say it was something you had 3% WV it would become 3 grams per hundred mil and if this was 5 % WV of an active ingredient it would become you guessed it 5 grams per hundred mil this part stays the same it's probably this little bit up here that changes the amount of grams okay and that's a concentration that we have here in a quite often constant that you will see concentrations are this sort of format where we have grams per mil or milligrams for meal or milligram food per liter but it's always in that you know where going weight per volume okay so I'm going to show you now how we can play around with this first off to work out a few things but just what I'm going to show you is just another way of writing this or another way of working out the concentration but not in grams per mil per mil which is a little bit cumbersome you'll find I'm going to show you how to work this out in terms of milligrams per mil okay this is a lot easier way of working with concentration because you can easily then convert things across and work things out as you'll see so first off what does say 10% 10% WV when's that going to meet what is that going to be this 10% of an active ingredient what's they going to be in milligrams per mil so first off you're put in jail okay this means 10 grams per hundred mil which is equal to their milligrams is a thousand milligrams in a gram so if I times ten to five thousand I'm gonna have ten thousand milligrams per 100 mil okay so the units are right milligrams are right and mills are right and I can now cancel things out so there's two zeros up here there's two zeros down there and I am left with 100 milligrams per mil but I'm going to show you just a little trick here a little shortcut if you want to easily go from this percentage here straight into milligrams Bentley wattage you know you can easily do this grams per mil if you want to put it straight away it's a milligrams bill just times by 10 okay so 10 times 10 is equal to 100 so say slightly differently if it was 3% don't want to know what it is in milligrams per mil well I just times it by 10 and it is 30 milligrams per mil okay or another way you can think of it is 3 grams per hundred mil okay so it's 2 as you do this so just give you one more of those so say I wanted to know what I've got harder one now 0.5 say the active ingredient was 0.5 % WV wait for volume what's it's in milligrams per mil we times it by ten point five times ten this would be five milligrams per mil of the active ingredient okay so you're going to say okay what of it it's sort of showing your halfway but this now we can use to work out a whole bunch of things it's the same for instance we had dextrose and it was one percent dextrose one percent WV and 20 mil of this particular solution is given I don't want to know how much of the active ingredient is given so so this was dextrose one percent 20 ml of the solutions given how much actual dextrose is given how do we work this out the way we do this is as follows the first thing I do is I change this into milligrams per mil okay it's a nice Universal sort of thing so 1 % WV is times 10 this is 10 milligrams per mil and 20 mil is given so there's 10 milligrams every mil 20 mil is given so at times just by 20 mil it tells us that 200 milligrams of active ingredient is given so that's why I had you changing those at the start because it's nice and easy way of doing this okay what about we go through another one of these types of questions so say we had 0.5% in concentration and 10 mil is given how much the active ingredient is given so how do we work this out well we're going to change this into milligrams per mil 0.5 times 10 is 5 milligrams per mil and then times 10 mil because for each meal we're getting 5 milligrams so 10 times 10 mil we are given 50 milligrams of teve ingredient so they are type of question in market with this is say for instance you had twelve point five grams of active ingredient which is glucose and this is in half a liter I don't want to know what the what is the % WV I want to know what that is I want to change it back to the initial part so how do we go about doing this well that's fairly simple you'd probably guess the first thing we're going to do is we are going to put this as a milligrams per mil so twelve point five and we are going to put this in milligrams per mil first and then instead of timesing by ten to get it back to the WL 9/10 yeah so once it's in milligrams four mil how many milligrams in twelve point five grams this is 12,500 milligrams how many mills is this this is 500 mil so I made sure the units are good and now just divide through so I'm going to get rid of zeros here this 0 this 0 this 0 this 0 125 divided by 5 is 25 milligrams per mil what is as the active ingredient percentage here well instead of times you buy 10 which were you were using to get to this stage from the to do this way I'm going to be going backwards so I'm going to divide by 10 this is 2.5% let's put a WV there just to be happy all right what about another question here say we have 1.6 grams of dextrose it's in 200 mil and I want to know you can guess it I want to know what the percent w/v is yeah well now that is as a concentration percentage so first off and I'll put this in milligrams per mil so what is this in milligrams per mil this is in grams under changement milligrams at times by a thousand this is 1600 milligrams this is already in milk this is 200 p.m. 1600 divided by 200 this equals 8 milligrams per mil and then dividing it by 10 together back to this percentage this is 0.8% WV all right anyway hopefully you found that video usable and well always happy to make more videos see you next time bye


  1. FABulous for pharmacy students as well. Thank you for making these simplified math vids. Too many profs just don't bother teaching WHY its logical to use shortcuts for concepts we can apply from background knowledge

  2. Blah, blah, blah. What it sounds like to me. I don't why anyone even cares when tools already exist that could work this out basically straight away.

  3. Hello. How do you say "hello" in Australian?
    Are you going to post some videos on integers?

  4. tecmath could u please tell me what does population density in points mean, for instance population denisty of africa is 36.4 kmsq. what does this point indicate please tell me

  5. WELCOME BACK! 👍🏻😊 Your channel was really helpful for me, so am excited for your return!!

  6. Hey Tecmath, Glad to see your still around. Really appreciate your math short cuts.
    Always enjoy your lessons

  7. This is perfect for my "street pharmacy" business. Anyone know where I can get a very accurate gram scale?

  8. HE IS BACK. This is an amazing channel that helps with soo much. You are a legend tecmath, keep up the work

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