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Measure twice, because you can only cut once

A character confuses measurements in some activity, resulting in having too little or too much of something that will become disastrous.

Could involve Explosive Stupidity in regards to the amount of gunpowder used or a similar explosive result, or Oven Logic when the result isn't explosive but distasteful or overwhelming.

This is Truth in Television, so Don't Try This at Home. Mismeasurements are responsible for vast amounts of human tragedy in Real Life.


Not to be confused with Unit Confusion. See also Misplaced a Decimal Point and Similar Item Confusion.


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     Anime And Manga  

  • In Black Butler, maid Maylene misread the instruction label of a detergent due to her poor eyesight, and used 30 cups instead of the required 3, causing a huge, bubbly mess. In her defense, it was in Roman numerals, and if you try to ask a farsighted person to distinguish between XXX and III from point-blank, you'll probably get the same result.

     Comic Books  

  • In the Polish Kajko i Kokosz comic books the evil knights would construct a siege tower to get over the town wall but at night the heroes would sneak into the knights' encampment and alter the plans just enough to foil the plan. Since the knights were too stupid to recheck the measurements they would end up with a ramp that was too short or too long and Hilarity Ensued.

     Comic Strips  
  • In a strip from the Boy Scout magazine Boy's Life, Pee Wee and Westy are charged with making cookies for a camping trip using a metric conversion of the recipe. They correctly make the conversion but over-bake the cookies when they get the baking time, the only measurement that wouldn't change, wrong. All is not lost as they pass off the crumbled cookies as granola.



  • In the film The Black Bird 1975 (a sequel/parody of The Maltese Falcon), the eponymous statue is mismeasured; it's one cubit long, about the length of a man's forearm, but the man who was measuring it is a Little Person so his arm is much shorter than normal.
  • In This is Spın̈al Tap, Nigel confuses the symbols for inches and feet while the band is brainstorming ideas for a visual accompaniment to their new song "Stonehenge". As a result, the stone model lowered onto the stage early in the song is 18 inches high.


  • This was a feature of many of Bergholt Stuttley "Bloody Stupid" Johnson's inventions on the Discworld. For a sample, his Colossus of Ankh-Morpork is currently carried in the Museum Curator's pocket for when tourists ask to see it, and a matching set of salt and pepper shakers he designed is currently in use as a grain silo.

     Live Action TV  

  • Jonathan Creek: In "Angel Hair", Jonathan is designing an illusion that centers around sawing a ventriloquist dummy in half. As the trick requires extra sets of feet for the dummy, he tells the dummy maker to be sure dummy has twelve feet. The dummy maker ends up delivering a 12 foot tall dummy.
  • An episode of The Cosby Show had Theo ask his older sister if she could tailor a fake designer shirt for him (he had previously claimed he owned one in order to impress a girl). Her measurements are off, resulting in the shirt having mismatched sleeves among other problems.
    • Ultimately averted as the shirt wound up resembling one made by an even more trendy designer.
  • In Home Improvement, Al remarks that Tim's philosophy is "Never measure, cut yourself."
  • In the Soviet Yeralash short Measure Seven Times a schoolboy takes the proverb "measure 7 times, cut once" too literally and makes a stool 7 times larger.note 
  • In Dad's Army, Jones inverts the intended proportions for porridge (one mug of oats to one jug of water), resulting in enough porridge to feed a hundred men.

     Newspaper Comics  

  • A Garfield strip had Jon asking Garfield about the right amount of chili powder to add to a dish that he was making. The resulting amount caused the entire dish to go poof (It might have been intentional, as Garfield then tells Jon to pitch it all out and order a pizza).

     Video Games  

  • In the "Where Are They Now?" Epilogue of Ghost Trick, Beauty and Dandy are shown trying to break into a safe using twenty kilograms of gunpowder.
    Beauty: Wait a minute. "Twenty KILOGRAMS"?! I thought it was twenty GRAMS...!


     Western Animation  

  • Hey Arnold!: When the town tries to bake the world-record largest pizza puff, Sid accidentally adds an absurdly large amount of baking soda because he reads "tsp" (for "teaspoon") as meaning "ten square pounds", resulting in a massive pizzasplosion.
  • The Simpsons: Homer is in the basement trying to invent something. He works out a few equations on the chalkboard, hammers, saws, welds, and finally blows up the basement. Walking over to a chart, he changes a "greater than" sign to a "less than" sign, and goes back to work. (This causes an even bigger explosion, and on the next review he finds and erases the "Dynamite" component from the diagram.)

     Real Life  

  • Nearly any unintentional drug overdose is a result of this, whether prescription, over the counter, illegal, or anything, whether it be on the side of the manufacturer (e.g. the pharmaceutical company mismeasures the amount of active substance needed in its pills, the drug dealer actually doesn't "cut" the heroin as much as usual) or on the side of the consumer (someone thinks they need to take more of a laxative or sleeping pill to make it work faster, someone drinks over their limit, someone assumes the pharma company or drug dealer to be trustworthy).
  • Quite a few fires and explosions can be attributed to various forms of mismeasurement. Classic forms include the following:
    • Not realizing that exceeding the amperage capacity of an electric power source is generally not a good idea, and doing things like plugging heaters/air conditioners/lots of electronics on a breaker strip into a low-capacity outlet, not checking the rating of extension cords and power strips and plugging things into them that should never be plugged into them.
    • The overuse of explosive, flammable, or combustible substances, such as in the barbecue example above, or "topping off" a vehicle or gas-powered lawnmower/leafblower/similar's gas tank.
    • Storing more than one needs to immediately use of those substances or of ammunition or fireworks/pyrotechnic devices in one location.
    • Having too much heat in a given space.
    • Mixing flammable, combustible, or explosive chemicals without proper knowledge of safe (or safer) measurements and outputs.
  • Crossing up units of measurement can be a disastrous form of this - the most famous example being the loss of the Mars Climate Observatory Orbiter by having one team use metric units and another using American Standard units.
    • This also happened to the Gimli Glider, resulting in the airliner running out of fuel and having to make an unpowered landing. Miraculously, there were no serious injuries.