How to read a tape measure in four steps
- Find the last inch number before the end of what you are measuring. That is the whole-inch part of the answer.
- Count the spaces past it. On a standard US tape each inch is split into 16 equal spaces, so every space is 1/16 inch.
- Put the count over 16 and reduce it. Five spaces is 5/16, which does not reduce. Ten spaces is 10/16, which reduces to 5/8.
- Put the two together. Five spaces past the 2 is 2 5/16 inches; ten spaces past the 2 is 2 5/8 inches.
With practice you stop counting and read the length of the line instead. A mark on a 1/8 line is always an odd number of eighths (1/8, 3/8, 5/8 or 7/8); a mark on a 1/4 line is 1/4 or 3/4. Try it with the practice mode on the tape above: it names a measurement and you find the line.
What each line on a tape measure means
The lines get shorter as the fractions get smaller, and the same pattern repeats in every inch:
- Inch lines are the longest and carry the numbers.
- The 1/2 inch line is the longest one between two numbers, right in the middle.
- The 1/4 inch lines come next, at 1/4 and 3/4.
- The 1/8 inch lines are shorter again, at 1/8, 3/8, 5/8 and 7/8.
- The 1/16 inch lines are the shortest, at every odd sixteenth.
Every mark on the tape, with its decimal and metric equivalent:
| Fraction | Sixteenths | Decimal (in) | Millimeters | Line on the tape |
|---|---|---|---|---|
| 1/16 | 1/16 | 0.0625 | 1.588 | 1/16 mark, shortest |
| 1/8 | 2/16 | 0.125 | 3.175 | 1/8 mark |
| 3/16 | 3/16 | 0.1875 | 4.763 | 1/16 mark, shortest |
| 1/4 | 4/16 | 0.25 | 6.350 | 1/4 mark |
| 5/16 | 5/16 | 0.3125 | 7.938 | 1/16 mark, shortest |
| 3/8 | 6/16 | 0.375 | 9.525 | 1/8 mark |
| 7/16 | 7/16 | 0.4375 | 11.113 | 1/16 mark, shortest |
| 1/2 | 8/16 | 0.5 | 12.700 | 1/2 mark, longest between the inches |
| 9/16 | 9/16 | 0.5625 | 14.288 | 1/16 mark, shortest |
| 5/8 | 10/16 | 0.625 | 15.875 | 1/8 mark |
| 11/16 | 11/16 | 0.6875 | 17.463 | 1/16 mark, shortest |
| 3/4 | 12/16 | 0.75 | 19.050 | 1/4 mark |
| 13/16 | 13/16 | 0.8125 | 20.638 | 1/16 mark, shortest |
| 7/8 | 14/16 | 0.875 | 22.225 | 1/8 mark |
| 15/16 | 15/16 | 0.9375 | 23.813 | 1/16 mark, shortest |
| 1 | 16/16 | 1 | 25.400 | Inch line, longest and numbered |
Some tapes go one step finer, with 1/32-inch lines, often only along the first 12 inches. Read them the same way: count the spaces past the inch, put the count over 32 and reduce. For every 64th of an inch as a decimal, see the fraction to decimal chart.
Reading feet and inches
Most US tapes number the inches all the way along instead of starting again at each foot, so the 64 on the blade means 64 inches. Each foot is usually marked as well, at 12, 24, 36 inches and so on, often in red. To turn inches into feet and inches, divide by 12: the whole number is the feet and the remainder is the inches.
- 64 inches = 5 × 12 + 4 = 5 ft 4 in, written 5' 4" (or 5'-4" on plans).
- 38 3/8 inches = 3 × 12 + 2 3/8 = 3 ft 2 3/8 in.
- 96 inches = 8 ft, the length of a standard sheet of plywood.
Red numbers and black diamonds
Two kinds of special marks help with framing layout.
Red numbers every 16 inches. Studs in walls and many floor joists are set 16 inches apart, center to center. Most US tapes print 16, 32, 48, 64, 80 and 96 in red, or on a red background, so you can mark the layout without adding up. Three 16-inch spaces make 48 inches, so the edges of 4-foot-wide sheets land on a stud.
Black diamonds every 19.2 inches. Many tapes also have a small black diamond at 19.2, 38.4, 57.6, 76.8 and 96 inches. That spacing is used for some engineered floor joists and trusses: it divides 8 feet into five equal spaces, so the ends of an 8-foot sheet land on framing. 19.2 inches does not fall on a sixteenth, which is why the diamonds sit between the regular lines.
| Mark from the end | 16 in spacing (red numbers) | 19.2 in spacing (black diamonds) |
|---|---|---|
| 1st | 16 in (1 ft 4 in) | 19.2 in (about 1 ft 7 3/16 in) |
| 2nd | 32 in (2 ft 8 in) | 38.4 in (about 3 ft 2 3/8 in) |
| 3rd | 48 in (4 ft) | 57.6 in (about 4 ft 9 5/8 in) |
| 4th | 64 in (5 ft 4 in) | 76.8 in (about 6 ft 4 13/16 in) |
| 5th | 80 in (6 ft 8 in) | 96 in (8 ft) |
| 6th | 96 in (8 ft) | – |
The "about" values are the nearest 1/16 inch. Both spacings meet at 96 inches, and 24-inch spacing needs no special mark: it falls on 24, 48, 72 and 96.
The hook and true zero
The metal hook at the end of the blade is loose on purpose. It slides back and forth by exactly its own thickness:
- Hooked over an edge, the pull slides the hook out, and the inside face of the hook is zero.
- Pushed against a wall, the hook slides in, and its outside face is zero.
Either way the tape reads from true zero. A hook that has been bent, or rivets that someone has tightened, throw off one kind of measurement or both. To check a tape, measure the same board both ways and compare.
For work where 1/32 inch matters, many woodworkers "burn an inch": they measure from the 1-inch line instead of the hook and subtract 1 inch from the reading. For an inside measurement, such as the width of a window opening, many tapes print the length of the case on its bottom. Butt the hook against one side and the back of the case against the other, read the blade where it leaves the case, and add the case length.
Metric and dual-scale tapes
A metric tape is marked in millimeters, with a longer line every 5 mm and a number every centimeter (10 mm). There is nothing to reduce: 23 centimeters and 7 small lines is 237 mm, or 23.7 cm. Many US tapes are dual-scale, with inches along the top edge and centimeters along the bottom, which makes a handy converter: 1 inch is exactly 25.4 mm, and 1/16 inch is about 1.6 mm.
Tips for accurate measuring
- Look straight down at the line. Reading from an angle shifts the mark you seem to see.
- Mark with a V. Draw a small V (a "crow's foot") with its point on the line instead of a single dash, so the mark does not drift.
- Use one tape for one project. Two tapes can differ by 1/32 inch or more over a few feet.
- Write fractions in lowest terms. 2 5/8 is easier to find again than 2 10/16, and it is how plans and cut lists are written.
Frequently asked questions
What are the fractions on a tape measure?
A standard US tape divides each inch into sixteenths. The longest line between two inch numbers is the 1/2 inch mark, the next longest are 1/4 and 3/4, then the eighths, and the shortest lines are the sixteenths. Some tapes add 1/32-inch marks, often only along the first 12 inches.
How do you read 1/16 on a tape measure?
{ "Find the last inch number before your mark, then count the spaces past it": { " Each space between two lines is 1/16 inch, so five spaces past the 2 is 2 5/16 inches": { " If the count is even, reduce it": "10/16 is 5/8, 4/16 is 1/4 and 8/16 is 1/2." } } }
Why are some numbers red on a tape measure?
Most US tapes highlight every 16 inches (16, 32, 48, 64 and so on), usually in red, because studs and joists are commonly set 16 inches apart, center to center. Three 16-inch spaces make 4 feet, so the edges of 4 × 8 sheets land on a stud.
What are the black diamonds on a tape measure?
Many tapes have a small black diamond every 19.2 inches, a spacing used for some floor joists and trusses. Five 19.2-inch spaces fit exactly in 8 feet (96 inches), so the ends of an 8-foot sheet land on framing. Not every tape has them.
Why is the hook on my tape measure loose?
It is meant to move. The hook slides by its own thickness so the tape reads from true zero both ways. It slides out when you hook it over an edge and in when you push it against a wall. Do not bend it back or tighten the rivets, or both kinds of measurement will be off.
How do you read feet and inches on a tape measure?
Most US tapes number the inches all the way along, so the 64 means 64 inches. Divide by 12 for feet; the remainder is inches. 64 inches is 5 feet 4 inches, written 5' 4". Many tapes also mark each foot, at 12, 24, 36 inches and so on.
Last updated October 17, 2026.