Converting Units of Measurement Worksheets

Converting units means writing the same measurement with a different unit, such as 3 feet as 36 inches. The six PDFs on this page have conversion tables for length, weight, capacity and time, in customary and metric units, and every sheet has an answer key. They follow standard 4.MD.A.1 of the Common Core standards for grade 4 measurement and data, and the notes below show when to multiply, when to divide and how the units connect.

Big units to small units

When you change a big unit into a smaller one, you need more of them, so you multiply. 1 foot is 12 inches, so 3 feet is 3 × 12 = 36 inches. Grade 4 children express measurements in a larger unit in terms of a smaller unit and record them in two-column tables (Common Core 4.MD.A.1), which is exactly what these worksheets practice.

Converting units worksheets: what is in the set

There are 6 converting units worksheets on this page, and every one has an answer key except for any cut-out games. The first three sheets cover length, weight and capacity, and time. The next two split metric from customary, and the last is a mixed review.

Converting units worksheets: big units to small units and back

The converting units worksheets have one rule that does all the work: when you change a big unit into a smaller one, you need more of them, so you multiply. When you change a small unit into a bigger one, you need fewer, so you divide. Wikipedia’s article on unit conversion shows how the same rule works for all kinds of units. This table shows twelve conversions, eight that multiply and four that divide:

The factor is always the same as the “1 big = ? small” fact: 1 ft = 12 in, 1 yd = 3 ft, 1 kg = 1,000 g and 1 hr = 60 min. A child who knows the fact knows both ways to convert. The times tables worksheets and multiplication worksheets pages help with the products.

Customary units conversion: feet, yards, pounds and gallons

The customary units conversion sheets are harder than the metric ones, since the factors are 12, 3, 16, 4 and 2, and not powers of ten. This table shows the main facts, with the chain that joins the units:

Many conversions use two steps. For 5 yards in inches, 5 yards is 15 feet, and 15 feet is 180 inches. This table shows three examples of the chain from yards to feet to inches:

The numbers in the last column are all multiples of 36, since 1 yard is 36 inches. A child who knows that 1 yard is 36 inches can do the conversion in one step.

Metric conversion worksheets: moving between kilo and milli

The metric conversion worksheets use the prefixes of the metric system. Every prefix is a power of ten, so converting means multiplying or dividing by 10, 100 or 1,000, and for whole numbers the digits only need new zeros. This table shows the seven prefixes and the units that use them:

Here are six conversions that grade 4 children make with whole numbers:

The metric ladder diagram above shows the same idea. Each step down the ladder from kilometer to meter, to centimeter and to millimeter multiplies by 1,000, 100 and 10. Grade 5 children extend this to decimals, as the Common Core standards for grade 5 measurement and data describe, and the decimals worksheets pages have the decimal work.

Measurement conversion worksheets: units of time

The measurement conversion worksheets with time are different from the others, because the factors are 60, 24 and 7, which are not powers of ten. Children have to learn them as facts. This table shows how many seconds there are in five units of time:

There are 86,400 seconds in a day and 604,800 in a week. These numbers show why seconds are not used for long times. A year of 365 days has 31,536,000 seconds. The telling time worksheets pages teach the hours and minutes on a clock, and the time calculator adds and subtracts times.

Conversion tables grade 4: two-column tables

The conversion tables grade 4 use are two-column tables, where the first column has the big unit and the second the small unit, in order. The standard 4.MD.A.1 asks children to record measurements in a two-column table, and to see the pattern. Each row goes up by the same number, which is the conversion factor. The diagram of feet and inches above is the example, with 12, 24, 36, 48, 60 and 72 inches for 1 to 6 feet.

A good activity is to make a table for a different pair of units. For gallons and quarts, the second column goes 4, 8, 12, 16 and 20, and for hours and minutes it goes 60, 120, 180 and 240. Children can then use the table to answer a question without calculating again. This table shows mixed measurements, and how to change each to the small unit:

Customary and metric: comparing the two systems

Children in the United States use both systems, so it is useful to know how big a metric unit is in customary units. This table gives six approximate facts. They are not exact, and they are not part of the grade 4 standard, but they help with a sense of size:

An inch is exactly 2.54 centimeters. The other values are rounded, and the real conversion is more precise. A child who knows that a meter is a little more than a yard has a good start.

Common mistakes with converting units

The biggest mistake is to multiply when the problem needs division, or the other way round. This table shows five mistakes, what went wrong and the fix:

Converting units word problems

Converting units comes up in cooking, building and travel. Ask children to decide whether the unit gets bigger or smaller, and then multiply or divide:

Games and activities for converting units

Children learn converting units best when they play with it. These games use things that are found at home or in a classroom:

• Unit hunt: find objects that are about 1 foot, 1 meter and 1 inch long, and measure them
• Conversion bingo: a bingo card with the answers, and calling cards with the conversions
• Human ladder: make a ladder of units on the floor, and step up or down for each conversion
• Recipe conversion: change a recipe from cups to quarts or from ounces to pounds
• Time race: say how many minutes are in 3 hours as fast as you can
• Table builder: make a two-column table for any pair of units, and ask a friend to use it

Extra support and extra challenge with converting units

For children who need more support: start with units that the child knows, such as feet and inches, and use a real ruler. Make a two-column table and find the pattern. Always ask “is the new unit bigger or smaller?” before multiplying or dividing. Do the sheets with one kind of unit at a time, and use the answer key to check.

For children who need more challenge: ask for the number of seconds in 2 hours, for a conversion with two steps, such as yards to inches, and for the sum of 2 ft 9 in and 1 ft 8 in. The sheet that mixes all the units, and the problems with mixed measurements, are good challenges.

How to tell that a child is ready to move on from converting units

Before moving on from converting units, check that the child can do all four of these things:

1. The child knows the main facts for length, weight, capacity and time.
2. The child decides to multiply or divide from the sizes of the units.
3. The child makes a two-column conversion table.
4. The child changes a mixed measurement to a single unit.

When all four are true, move on to the measuring length page, or the area and perimeter page.

A 20-minute lesson on converting units

A short lesson is the best way to introduce converting units. This 20-minute plan can be used in a classroom, at a tutoring session or at home, and it uses the worksheets at the end:

Where converting units fits across the grades

No skill stands alone. This table shows what children learn before and after converting units, with the standard that goes with each step:

This page is the main page for unit conversion. The whole sequence is on the measurement worksheets page.

Helping at home with converting units

Parents do not need to be experts to help with converting units. These suggestions work well, and each takes only a few minutes:

• Cook together and change cups to pints or ounces to pounds.
• Ask “how many minutes in 2 hours?” while waiting.
• Use a ruler and a tape measure to find how many inches are in a foot.
• Look at labels, which show both customary and metric units.
• Say “bigger to smaller means multiply” until it is automatic.

How to check progress in converting units

A teacher or parent can check progress in converting units with the answer key and a few questions. This table shows three common situations, what they mean and what to do next:

A five-day plan for converting units

Most children need about a week of short sessions for converting units. This plan follows the order of the worksheets on this page:

When the plan for converting units is complete, move on to the measuring length page. The whole sequence is on the measurement worksheets page.