How long is a foot? The answer is somewhere around 12 inches. But the exact length is an ongoing debate. Now change is afoot.
Here’s the problem: There are two different measurements for a foot. The difference is so small it can’t be seen on a regular ruler. But over large distances, the difference matters, especially to folks like land surveyors and architects.
Remember the Bible example of two measuring devices? Deuteronomy 25:13 admonishes against “two kinds of weights, a large and a small.” Evidently, ancient merchants used light stones on their side of the balance when selling and heavy ones when buying. Merchants with different measurements were cheating both ways.
Those who devised different foot lengths weren’t cheating. But the results were similarly thorny. How wonderful to know that God judges, weighs, and measures perfectly on our behalf!
Some surveyors use what’s known as the U.S. survey foot. Others use a measurement more accepted worldwide: the international foot. The international foot is newer and just a bit shorter. The difference comes out to less than 0.02 inch per mile. That’s just 28.3 feet when measuring the width of the whole United States!
Here’s what happened: In 1933, the U.S. government defined a foot as 1,200 meters divided by 3,937. That’s 0.3048006 meters. (Even more decimals to be exact. But who’s counting?)
Years later, someone lopped off those last three digits. After all, 0.3048 meters was simpler. That measurement became the international foot.
Measurement mayhem began in 1959. That’s when the federal government told everyone to use the international foot. However, surveyors could keep using the old U.S. foot “for a while.”
That “while” has lasted six decades.
Surveyors in 40 U.S. states and territories still use the longer U.S. foot. The rest use the shorter international one. The result?
“We have chaos,” says Michael Dennis, a project manager for National Geodetic (math of Earth’s curve) Survey.
The difference between the two feet caused trouble in planning a California high speed rail. It created a mess for bridge work between Oregon (international foot) and Washington (U.S. foot).
“It’s embarrassing that we even had this going on for 60 years,” Dennis says. “This whole thing is ridiculous.”
Dennis realizes the U.S. foot “sounds very patriotic, very American” to some people. But he thinks it makes sense to use the same measuring stick as the rest of the world.
The federal government agrees. Officials want to reduce the chance for errors and confusion. In 2022, they’ll give the U.S. foot the boot. In other words, it won’t have a leg to stand on.