Skip to content
DoseReady

Practice problems · Conversions · 5 worked

Unit conversion practice problems for nursing students

A conversion problem asks you to restate a dose, a weight or a volume in another unit, such as milligrams in grams or fluid ounces in milliliters. The arithmetic is a single factor. The easy slip is turning that factor upside down, and then the answer is off by the factor squared: a million times between milligrams and grams.

The rounding rule on this page

Every answer here is rounded once, at the end, under one stated rule: 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. Your program's rule may differ, and on an exam it is the one that counts.

Work each problem on paper first, then open its solution. Each one is one of the 20 problems in DoseReady's Conversions family, with the numbers the app drew for it.

No licensed clinician has reviewed the problem set. Where a problem and its source disagree, trust the source and what your program teaches.

Problem 1 of 5

An intravenous vancomycin dose is ordered as 1,500 mg. The vials stocked on the unit are labeled in grams. Express the ordered dose in grams.

Show the worked solution

Dimensional analysis

1,500 × 1 ÷ 1,000 = 1.5

Ratio and proportion

  1. 1,000 mg is to 1 g as 1,500 mg is to x

    1,500 × 1 ÷ 1,000 = 1.5

    x = 1.5 g

Formula method

The formula method (D ÷ H × Q) does not fit this problem. The chain above is the working.

The working comes to
1.5 g
The answer under the stated rule
1.5 g
Nearest tenth, half rounds up.

What each slip gives here

  • Decimal point one place out15 g or 0.2 g
  • Conversion factor inverted1,500,000 g
  • Conversion skipped1,500 g
  • Rounded to the wrong precision2 g

“Rounded to the wrong precision” is the same working rounded to some other step, such as a half, a quarter or a hundredth, or left unrounded.

What this problem is built from

Problem 2 of 5

A refill order for levothyroxine is written as 0.1 mg daily. The pharmacy stocks levothyroxine tablets labeled in micrograms. Express the ordered dose in micrograms.

Show the worked solution

Dimensional analysis

0.1 × 1,000 ÷ 1 = 100

Ratio and proportion

  1. 1 mg is to 1,000 mcg as 0.1 mg is to x

    0.1 × 1,000 ÷ 1 = 100

    x = 100 mcg

Formula method

The formula method (D ÷ H × Q) does not fit this problem. The chain above is the working.

The working comes to
100 mcg
The answer under the stated rule
100 mcg
Nearest tenth, half rounds up.

What each slip gives here

  • Decimal point one place out1,000 mcg or 10 mcg
  • Conversion skipped0.1 mcg

What this problem is built from

Problem 3 of 5

An infant's admission weight is documented as 5 kg. The neonatal flow sheet tracks daily weights in grams. Express the weight in grams.

Show the worked solution

Dimensional analysis

5 × 1,000 ÷ 1 = 5,000

Ratio and proportion

  1. 1 kg is to 1,000 g as 5 kg is to x

    5 × 1,000 ÷ 1 = 5,000

    x = 5,000 g

Formula method

The formula method (D ÷ H × Q) does not fit this problem. The chain above is the working.

The working comes to
5,000 g
The answer under the stated rule
5,000 g
Nearest tenth, half rounds up.

What each slip gives here

  • Decimal point one place out50,000 g or 500 g
  • Conversion skipped5 g

What this problem is built from

Problem 4 of 5

A patient's urine output for the past day totals 2,600 mL. The daily fluid balance summary reports volumes in liters. Express the output in liters.

Show the worked solution

Dimensional analysis

2,600 × 1 ÷ 1,000 = 2.6

Ratio and proportion

  1. 1,000 mL is to 1 L as 2,600 mL is to x

    2,600 × 1 ÷ 1,000 = 2.6

    x = 2.6 L

Formula method

The formula method (D ÷ H × Q) does not fit this problem. The chain above is the working.

The working comes to
2.6 L
The answer under the stated rule
2.6 L
Nearest tenth, half rounds up.

What each slip gives here

  • Decimal point one place out26 L or 0.3 L
  • Conversion factor inverted2,600,000 L
  • Conversion skipped2,600 L
  • Rounded to the wrong precision3 L or 2.5 L

“Rounded to the wrong precision” is the same working rounded to some other step, such as a half, a quarter or a hundredth, or left unrounded.

What this problem is built from

Problem 5 of 5

A patient drinks 8 fl oz of juice with breakfast. Oral intake is charted in milliliters. Express the intake in milliliters.

Show the worked solution

Dimensional analysis

8 × 30 ÷ 1 = 240

Ratio and proportion

  1. 1 fl oz is to 30 mL as 8 fl oz is to x

    8 × 30 ÷ 1 = 240

    x = 240 mL

Formula method

The formula method (D ÷ H × Q) does not fit this problem. The chain above is the working.

The working comes to
240 mL
The answer under the stated rule
240 mL
Nearest tenth, half rounds up.

What each slip gives here

  • Decimal point one place out2,400 mL or 24 mL
  • Conversion factor inverted0.3 mL
  • Conversion skipped8 mL

What this problem is built from

Practice under your own program's rules

In DoseReady you enter your program's passing score, notation and rounding rule once. Every answer is graded under that rounding rule, and each worked solution is written in your notation where the problem allows it.

Coming to the App StoreiPhone

Exam practice, never for patient care.

Guides

Other problem families