United States Customary Units System and Conversions
The United States customary system (USCS or USC) is the measuring system the typical American uses in everyday life: ounces, pounds; inches, feet, yards, miles; teaspoons, tablespoons, cups, pints, and gallons. In this section, we will look at the conversions for each of the commonly used units we may encounter in the healthcare setting. Pay close attention to the bolded information-it is used abundantly in medication administration
Weight
1 pound = 0.4545 kg and the reverse of that is 1 kg = 2.2 pound
1 ounce = 28 g
Length
1 foot = 30.48 cm
1 inch = 2.54 cm
Volume
1 gallon = 3.8 l
1 quart = 0.96 l
1 pint = 480 ml
1 cup = 240 ml
1 tablespoon = 15 ml
1 teaspoon = 5 ml
1 fluid ounce = 30 ml
Converting from the US Standard to Metric is a common task in nursing, both for medication administration and for keeping track of intake and output. Run through these practice problems to sharpen your skills
An oral medication in the amount of 45 ml is to be given. How many tablespoons will you give?
3 tablespoons Recall that 1 tablespoon equals 15 ml, thus 45 ml/15 = 3 tablespoons
A patient states her height is 5 foot 4 inches. What is her height in cm?
162.56 cm 5 foot 4 inches can be converted to inches by multiplying 5 (feet) and 12 (inches in a foot) first, then adding the 4 inches... this gives you 64 inches. Then multiply that by 2.54 (cm per inch)
The same patient states her weight is 140 pounds. How many kg is that?
63.64 kg There are 2.2 pounds per kg, so take the 140 pounds and divide by 2.2 to find kilograms. Then round to the hundredth. *Follow facility or school guidelines on whether to round to hundredths or tenths with patient weights
1.5 inches of Nitro paste topical is ordered. How many cm of paste is needed?
3.8 cm There are 2.54 cm per inch... thus, 1.5 x 2.54 is 3.81... remember to round medication doses to the tenth if greater than 1 and to the hundredth if less than 1
A patient has consumed 1 1/2 cups of milk, how many ml is that?
360 ml Recall that 1 cup = 240 ml... therefore, multiply 1.5 and 240 to get 360
A patient states he lost 10 pounds in the past month without dieting. How many kg did he lose?
4.55 kg Take 10 and divide by 2.2, then round to hundredth
A medication of 100ml is to be given with 8 fluid ounces of water. What is total volume to give in ml?
340 ml Recall that 1 fluid ounce = 30 ml, therefore 8 fluid ounces = 240 ml; then add the 100 ml of medication for a total of 340 ml
Ordered is 10 ml of an antibiotic. There are tablespoon and teaspoon cups available. How many of each could be used?
2 teaspoon or 0.67 tablespoon 1 teaspoon is 5 ml and 1 tablespoon is 15 ml... so 10 divided by 5 = 2 teaspoon or 10 divided by 15 = 0.67 tablespoon after rounding to the hudredth
A patient drank 1/2 cup juice and consumed 6 fluid ounces of jello, but vomited 300ml. How many ml did the patient retain?
0 ml 1/2 cup = 120 ml and 6 fluid ounces = 180 ml... therefore the patient consumed 300 ml and vomited an equal amount