3149: Measure Twice, Cut Once

Measure Twice, Cut Once

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Title text: "Measure zero times, cut zero times." --carpenter who has achieved enlightenment and realized the wood is fine where it is

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Explanation

This is one of 52 incomplete explanations: This page was created BY A REALLY BAD METALWORKER. Don't remove this notice too soon. If you can fix this issue, edit the page!

As indicated in the comic, "Measure twice, cut once" is a proverb, which means that planning and checking multiple times before acting is less costly than the mistakes that can follow from not doing so. In many trades such as carpentry the proverb is literal: material such as wood, leather, textiles, etc. cannot be un-cut once it is cut, so it is always less costly to double-check a measurement than it is to cut with the wrong measurement and have to buy replacement material for a second attempt.

The metaphor is of marking the place on a piece of material where you plan to cut and then verifying that measurement before cutting, to avoid the later waste involved in either trimming down the cut piece, or starting again with a whole new piece, if it turns out the first measurement was in error. (Randall claims it as a "carpentry proverb", but in fact it is not clear what it specifically originates in reference to, and it could equally well apply in a literal sense to other activities such as tailoring, leather-working, and so on.)

The comic takes the proverb literally, consisting of a graph of various activities involving measuring and/or cutting, showing the number of cuts made versus measurements (though it does not provide actual values). From most to least measurements (top to bottom in the plot):

Surveyor (≥4 measurements, ~0 cuts)

Surveyors have the task of measuring land. They measure boundaries, elevations, and distances, but are rarely asked to physically cut anything themselves; they only produce measurements and maps, for which they typically would make multiple measurements to ensure accurate and thorough charts for those who will make later use of them.

Surveyors often need to clear trees and bushes from a property line to be able to see or measure from one corner to another. These are called "cuts" in some American jargon.

Surgeon (~3 measurements, ~1 cut)

Surgery is a task requiring a great deal of precision, being on a living creature, not an inanimate object, and therefore having far less room for error. Extensive measurements and diagnoses must be performed prior to making cuts, but cuts are still made. The cuts are minimal (once, when possible) and must be deliberate and precise. This positions the surgeon at beyond even the Good Carpenter for the number of pre-cut measurements.

Good Carpenter (~2 measurements, ~1 cut)

A good carpenter would measure twice and cut once, if following the archetypal proverb.

Careless Carpenter (~1 measurement, ~1 cut)

A careless carpenter would measure just once, then cut once, not following the proverb. This could lead to simple mistakes that create pieces that don't actually fit, and thus waste wood (and/or time) in order to fix the issues.

Really Bad Carpenter (<1 measurement, ~2 cuts)

A particularly poor carpenter would not always measure even once (here indicated by being slightly lower on the plot than the presumed 1-measurement position) and cut twice or more, almost following the proverb in reverse. It also suggests that they may not merely have not measured correctly, but aren't even skilled enough to have tried to apply the correct measurements in the first place. While a careless carpenter might muddle through with the occasional error, it is likely that the really bad one makes even more mistakes and wastes even more wood.

Serial Killer (0 measurements, ≥3 cuts)

Would not normally require any particular attempted measurement at all, depending upon their particular modus operandi. But if this involves knives, multiple victims would necessarily require potentially large amounts of cutting, stabbing, slashing, etc. The placement at about the 3-cuts mark may also be a reference to a serial killer being characterized as having killed at least three people. However, measuring might be necessary if it was a sword designed by the killer.

Title text

The title text mentions a carpenter who does zero measuring and zero cutting. This is depicted as the epitome of expertise, because they have apparently achieved a superior philosophical enlightenment towards their task, perhaps being able to achieve their aim with the materials exactly as already provided by fate, or to adjust their aims to align with the existing reality of the universe.

Transcript

This is one of 27 incomplete transcripts: Don't remove this notice too soon. If you can fix this issue, edit the page!

a caption saying "measure twice cut once -carpentry proverb" with boxes around twice and once

[a scatter plot with x and y axis labeled number of cuts and number of measurements respectively, under the caption, with labels.]

on the scatter plot lies 6 differently labelled points:

surveyor: very high number of measurements, no cuts

surgeon: high number of measurements, almost middling number of cuts

good carpenter: middling number of measurements, same number of cuts as surgeon

careless carpenter: a number of measurements slightly lower than the good carpenter, same number of cuts as good carpenter

really bad carpenter: low number of measurements, high number of cuts

serial killer: no measurements, very high number of cuts

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Discussion

Measure once, shame on you. Cut twice, shame on me! StapleFreeBatteries (talk) 00:57, 2 October 2025 (UTC)

You know, that's not a bad proverb! RadiantRainwing (talk) 00:58, 2 October 2025 (UTC)

I will cut you! Shame on me. 82.13.184.33 08:49, 2 October 2025 (UTC)

This is my first XKCD explained! 108.254.160.57 00:59, 2 October 2025 (UTC)

Hip hip hooray for you! You did a great job. RadiantRainwing (talk) 01:02, 2 October 2025 (UTC)

OK - but how many times did you check it before saving? 82.13.184.33 08:49, 2 October 2025 (UTC)

A fundamental problem with this comic is that a "good carpenter" really means "an efficient carpenter" (true of any craftsman, really). Economy of motion, skilled enough to know when to be really precise and to know when precision doesn't matter and is a waste of time. The efficient carpenter doesn't need to measure twice, he or she gets it right on the first try. Or, consistent with the above, knows their capabilities well enough so they can only measure twice when it's truly necessary. And, of course, some of the best efficiencies come from not "measuring" at all — using an end stop or a jig so the cut is easy and repeatable without measurement. Drawing a line (or cutting without a line) against the actual reference point rather than against an intermediate measurement tool (some might call this "scribing," but that suggests a level of precision that isn't what I mean). Effectively, "measure zero times, cut once." And in the opposite, sometimes the most efficient approach is not to measure at all (whether numerically or against a reference object), but to make a rough cut and then a finish cut — effectively, "measure zero times, cut twice." Also possible is if you are gang cutting a stack of N boards, you measure 0 times or once and then make 1 cut, so on a per-board basis it's measure once, cut 1/N. I don't know that all of these things are obvious, per se, but I can't help feel surprised that they don't seem to have been considered. JohnHawkinson (talk) 06:38, 2 October 2025 (UTC)

That seems to be more of an issue with the proverb, rather than the comic. 82.13.184.33 08:49, 2 October 2025 (UTC)

Are you saying my wall with studs just butt ended atop one another isn't good enough? Oh, fine then, I'll go add some bracing and maybe nails. SDSpivey (talk) 11:07, 2 October 2025 (UTC)

PLEASE STOP, YOU'RE KILLING ME!!!! --DollarStoreBa'al^converse 13:08, 2 October 2025 (UTC)

I do not concur. (At least not fully...) When cutting timber, there are usually two dimensions to measure, and to make the perfect cut you must somehow have measured those to dimensions. A surgeon, on the other hand, must also use the third dimension, knowing how deep into the body they cut.

Then, obviously, there are situations that differ. Say you want to half something, cutting along the diagonal. Or if you amputate a leg. But usually! :) Fomalhaut (talk) 11:37, 3 October 2025 (UTC)

Somewhat disappointed there's no joke about quantum mechanics, even in the title text. I guess figuring out how to fit the uncertainty principle here is left as exercise to the reader? 164.90.218.225 10:44, 2 October 2025 (UTC)

The title text seems to reference the Taoist concept of the uncarved block - https://en.wikipedia.org/wiki/Pu_(Taoism) 70.124.160.162 (talk) 13:18, 2 October 2025 (please sign your comments with ~~~~)

Possible reference to the real-life use of the reverse proverb (measure once cut twice) which is used by many makers. I am familiar with the concept from Adam Savage, but I don’t know if he’s the originator. The idea is that measurement is actually too imprecise of a tool and should only be used as an approximation. The final size of a piece will be based on something like a pressure fit. 98.36.13.95 (talk) 14:24, 2 October 2025 (please sign your comments with ~~~~)

About the title text, would the carpenter have to look or otherwise measure the wood to assume it's fine? Measure once, cut 0 times. -- L0L0Z1993 (talk) 15:19, 2 October 2025 (please sign your comments with ~~~~)

two measures one cut 2A0E:1D47:9098:3800:1126:180F:44A0:E826 18:07, 2 October 2025 (UTC)

Isn't this the 20th anniversary of XKCD? Strange that Randall wouldn't make a special comic! 92.92.106.219 18:27, 2 October 2025 (UTC)

Depends upon what you count the start as.

Also, is 20 years special enough to mark..? Maybe 0x20 years! Or 0x2A... 82.132.215.216 19:26, 2 October 2025 (UTC)

My favorite option: "Measure never, cut forever!" Heard Bec Hill say this on the podcast A Problem Squared (don't ask me which episode). Couldn't find much about it online so for all I know she came up with it. It's catchy! --NeatNit (talk) 20:06, 2 October 2025 (UTC)

What about other professions or trades? Is it the number of cuts or number of things cut? Is sawing a series of cuts or just one cut?

• Barber: if comparing hair length counts as measuring, about 1:1 to 1:3 measure:cut ratio, since they sometimes snip-snip-snip a line of hair they're holding between two fingers. If measuring excludes estimating, then they're way to the right of serial killers. Do clippers count as cutting?
• Gardener: probably about the same as barbers; more actual measurement likely.
• Film director: Mostly 'cut', I think.

TimBav (talk) 13:18, 3 October 2025 (UTC)

Barbers basically are serial killers... (Or, as it turns out, lumberjacks, who cut cut cut.) 81.179.195.93 18:38, 3 October 2025 (UTC)

Sawing has to count as just one cut, otherwise the phrase doesn't make sense for carpenters where it originated. --NeatNit (talk) 17:38, 14 October 2025 (UTC)

Here's an exception to the 'Surgeon' category. And another similar one, though not with a physical cutting device. 81.179.195.93 18:19, 4 October 2025 (UTC)

Laproscopic surgery requires many cuts, and I'm not sure, but I think many surgeries require an initial cut to get to the problem and other cuts to fix the problem. Sometimes there are multiple problems requiring multiple cuts (such as in a shooting where the holes need operation. I suppose that could be called multiple surgeries.... But serial killing could be multiple tasks as well. -- 208.38.240.15 (talk) 14:59, 6 October 2025 (please sign your comments with ~~~~)
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