Read a tape measure in one glance, sixteenths and all

Quick answer: Don't count lines up from the inch. Find the nearest quarter, then count one or two short lines up or down. On a standard tape, no sixteenth is ever more than two marks away from a quarter.

The fastest way to spot a green hand on a framing crew is to ask him for a number. The lead calls out "what've you got?" and the new guy squints at his 25-foot tape, touches the blade with a fingernail, and says, "Twenty-three inches and... one, two, three, four, five, six, seven, eight, nine, ten, eleven of the little ones." Everybody's waiting. The saw's spinning down. Somebody sighs.

That number is 23 and 11/16. A guy who reads tape for a living sees it in under a second, and you can too in about a week of deliberate practice.

The lines already tell you what they are

Every inch on a standard tape is cut into sixteen pieces. The marks aren't all the same height, and that's the whole trick. The height of the line is the fraction.

• Tallest: the inch, with the number on it.
• Next tallest: the half, dead center.
• Next: the quarters, at 1/4 and 3/4.
• Shorter: the eighths, at 1/8, 3/8, 5/8 and 7/8.
• Shortest: the sixteenths, every odd one in between.

Some tapes print 1/32 marks on the first foot for finish work. Ignore them until you're doing trim or cabinets.

Read from the landmarks, not from zero

Your eye finds big lines instantly. So use them.

Say the blade lands just past the half. You don't count. You see the half, you see one short line past it, and you know it's 9/16. Two lines past the half is the eighth, so 5/8. Just shy of the next inch and one tiny line short? 15/16.

Practice it this way:

1. Find the inch.
2. Find the nearest of these: the inch, the 1/4, the 1/2, the 3/4.
3. Count up or down. One short line is a sixteenth. A slightly taller one is an eighth.

The 11/16 that took our new guy eleven counts is just the 3/4 mark, minus one sixteenth. "Three-quarter shy a sixteenth" becomes 11/16 after you've said it a few hundred times, and then you stop translating at all.

Say it the way the crew says it

Nobody on a job site says "ten-sixteenths." Reduce it. 10/16 is 5/8. 4/16 is 1/4. 12/16 is 3/4. If the top number's even, cut both in half until it isn't. Only odd sixteenths stay sixteenths.

You'll also hear the shorthand, and you should use it:

• Strong or fat means a hair over the mark. "Thirty-one and a quarter, strong."
• Shy or bare means a hair under.
• Plus or minus a sixteenth, when it's a full sixteenth off.

That's not slang for its own sake. "Seventy-two and a half, shy" tells the guy on the saw precisely which side of the line to cut, which saves a board.

Most crews also call everything in inches under about eight feet. Ninety-two and five-eighths beats "seven foot eight and five-eighths" when someone's punching it into a cut list. Ask your lead which way your crew does it, then do it that way.

The hook is loose on purpose

Every apprentice eventually decides the wiggly hook on the end is broken and crimps the rivets tight. Don't.

The hook slides exactly the thickness of the hook itself. Pull the tape against an edge and it slides out, so the measurement starts at the inside face of the hook. Push the tape into a corner and it slides in, so the measurement starts at the outside face. That's "true zero," and it's the only reason a tape is accurate both ways.

Drop a tape off a ladder enough times and the hook bends. Then it lies to you. Check it by measuring something both ways, hooked and pushed. If you don't get the same number, either replace the tape or burn an inch: line up the 1-inch mark on your edge instead of the hook, then subtract an inch from what you read. Write it down if you're doing that, because forgetting to subtract is how you cut a whole stack of blocking an inch short.

Inside measurements and the number on the case

For a window opening or the space between two studs, push the tape against one side, butt the case against the other, read the blade where it enters the case, and add the length of the case. That number's printed on the back of most tapes. Read yours tonight so you're not guessing tomorrow.

Or skip the math: bend the blade into the corner and read it there. It's a little less precise, but it's fine for rough framing.

The red numbers and the black diamonds

Most American tapes print every 16 inches in red or in a box. That's standard stud and joist spacing on center. Hook the end of a plate, and the red marks tell you where every stud lands down the wall.

The small black diamonds come every 19-3/16 inches. That's the spacing some engineered floor and roof systems use, five spaces to an eight-foot sheet. If you've never been on a job that uses it, you might go years without needing them. When you do, you'll be glad you knew what they were.

If you're still deciding which branch of carpentry you're heading into, which kind of carpenter to be and what each one pays lays out the work behind those marks.

Do the math in sixteenths

Adding 3/8 to 11/16 in your head feels hard because you're juggling two denominators. Use one. Turn everything into sixteenths: 3/8 is 6/16. Add 11. That's 17/16, which is 1 and 1/16.

Subtracting for a saw kerf, a reveal or half of a board's thickness works the same way. A 2x4 is actually 1-1/2 inches thick, so half of it is 3/4, which is 12/16. Get comfortable with the full list:

• 1/8 = 2/16
• 1/4 = 4/16
• 3/8 = 6/16
• 1/2 = 8/16
• 5/8 = 10/16
• 3/4 = 12/16
• 7/8 = 14/16

Know that cold and you'll stop reaching for your phone calculator, which, on a roof, is a phone you might not see again.

The mistakes that cost you a board

Reading upside down. Pull the tape left-handed or from the other direction and a 6 becomes a 9. Many tapes print the numbers on both edges for exactly this reason. Read the edge that's right side up.

Reading the wrong side of the mark. A pencil line has width. Make a "crow's foot," a small V whose point lands right on the number, instead of a fat dash. Then cut on the waste side of the line, not through it.

Using two different tapes. Two tapes out of the same truck can disagree by a sixteenth or more over ten feet. Measure and cut with the same tape. On a crew, check yours against the lead's on day one.

Trusting a sagging blade. On a long run the blade droops and reads long. Have someone hold the hook or tack a nail and keep it taut.

A ten-minute drill that actually works

Ask a buddy, a spouse or one of your kids to pull your tape to a random spot and pinch it. You call the number out loud, reduced, in one breath. They check. Do twenty. Then switch: they call a number, you find it on the blade as fast as you can.

It's boring. It's also the fastest way to stop being the guy everybody waits on. A week of that before your first day matters more than any gadget you could buy. If you're still filling your bags, the tools a first-year apprentice should actually buy puts a good 25-foot tape near the top of the list, and it's right to.

Where a laser beats it, and where it doesn't

A laser distance measurer is great for estimating a room, a ceiling height or a long run you'd otherwise need a second person to hold. Use one.

But it won't hook a board, mark a stud layout or ride on your belt through a 10-hour day of cuts. The tape's still the tool. It has to come out of the holster and back again without you thinking about it, like a pencil.

The lead won't remember the day you learned to read it. He'll remember every day you couldn't.