Free Printable Ruler Worksheets with Answer Keys

Four free PDF worksheets for practicing how to read a ruler: inches to the quarter, inches to the sixteenth, centimeters and millimeters, and measuring real lines. Each one has an answer key.

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Previews of four ruler worksheets: reading inches to the quarter, reading inches to the sixteenth, reading centimeters and millimeters, and measuring lines

Four free worksheets for practicing how to read a ruler, each a two-page PDF: the worksheet, then an answer key. Choose US Letter or A4 to match your paper. They start easy and get harder, so you can hand them out in order.

1. Reading inches: halves and quarters

Worksheet: reading a ruler in inches to the quarter inch

Eight rulers marked in quarter inches, each with an arrow. Students write the measurement, such as 2 ½ in or 3 ¾ in. A good first sheet for 3rd grade.

Download: US Letter PDF · A4 PDF

2. Reading inches: eighths and sixteenths

Worksheet: reading a ruler in inches to the sixteenth inch

The same layout on a full ruler with 1/16 inch marks, the kind used in shop class, sewing and DIY. Answers are written in lowest terms, such as 1 ⅜ in or 4 9/16 in.

Download: US Letter PDF · A4 PDF

3. Reading centimeters and millimeters

Worksheet: reading a ruler in centimeters and millimeters

Eight 15 cm rulers. Students write each reading twice, in centimeters and in millimeters (4.7 cm = 47 mm), which also practices converting between them.

Download: US Letter PDF · A4 PDF

4. Measure the lines

Worksheet: measure the lines in inches and centimeters

Twelve lines drawn at their true length. Students measure six in inches, to the nearest quarter inch, and six in centimeters and millimeters with a real ruler. Print this one at 100% scale (“Actual size”), and check the 1-inch bar at the top before copying.

Download: US Letter PDF · A4 PDF

Teaching tips

  • Start from the long lines. On an inch ruler, the longest marks are whole inches, then halves, quarters, eighths and sixteenths, each shorter than the last. Have students name the mark’s length before they count.
  • Count back from the next inch. For 2 ⅞, it’s often easier to see “one eighth before 3” than to count seven eighths up from 2.
  • Always simplify. 4/8 is ½ and 12/16 is ¾. The answer keys use lowest terms.
  • Metric is decimal. Each small mark is 1 mm, and 10 mm make 1 cm, so 4 cm and 7 small marks is 4.7 cm, or 47 mm.

For a full explanation with a diagram, see how to read a ruler. The fraction to decimal chart is a handy reference for older students.

No rulers in the classroom?

Print the free printable ruler (12 inch and 30 cm) on card stock, or use the online inch ruler on a tablet or laptop after a quick card calibration.

Frequently asked questions

What grade are these ruler worksheets for?

Under the US Common Core standards, measuring to the nearest inch starts in 2nd grade, halves and quarters come in 3rd grade (3.MD.4) and eighths in 4th grade (4.MD.4). Sixteenths usually come later, in middle school or shop class. The metric sheet suits grades 3 to 5, and all four work for adults brushing up for DIY or sewing.

Are the worksheets free to use in class?

Yes. Print as many copies as you like for your class, homeschool or tutoring. Please share the link to this page rather than re-uploading the PDFs elsewhere.

Do I need to print them at a special size?

The three reading worksheets work at any size. The 'measure the lines' sheet must be printed at 100% ('Actual size'), or the answers won't match. It has a 1-inch check bar: measure it before you hand the sheets out.

What if students don't have a ruler?

Print our free printable ruler on the same printer, or let them use the on-screen ruler on a calibrated tablet or laptop.

More measuring guides