How Long Is a Slinky When You Stretch It All the Way?

The claim that a standard Slinky stretches to 87 feet has bounced around the internet for years, but the reality is a bit more complicated—and more interesting—than that single number suggests.

Here's what's actually going on: A classic metal Slinky is made from 67 to 80 feet of flat steel wire, depending on whether you're holding an original 1945 version (80 feet) or a modern standard Slinky (closer to 67 feet). That wire is coiled into about 90-98 turns, creating the 2.25-inch compressed spring we all know and love.

So Where Does 87 Feet Come From?

The 87-foot figure seems to be either a misremembering of the wire length, or possibly refers to some theoretical maximum if you stretched a Slinky until it permanently deformed. But that's not how Slinkys are meant to work—and it's definitely not a measurement you'll find in official specs.

In practical terms, you can stretch a Slinky to about 15 feet in length as a helix without ruining it. Push beyond that, and you're entering the danger zone where your Slinky becomes a tangled mess of regret.

The Original Engineering

When naval engineer Richard James invented the Slinky in 1945, he spent over a year perfecting the specifications. He settled on high-carbon steel wire less than a sixth of an inch wide, coiled 98 times into a two-inch helical spring. The result? A toy that could "walk" down stairs with mesmerizing grace.

The beauty of the Slinky lies in its physics. That 67-80 feet of wire, compressed into just over two inches, creates the perfect balance of:

• Flexibility to transfer wave energy down stairs
• Tension to maintain its spring shape
• Weight (about half a pound) for smooth, controlled motion

Fun Slinky Numbers

Beyond the wire length confusion, here are some verified Slinky facts: Over 300 million Slinkys have been sold since 1945, making it one of the most successful toys in American history. If you connected all those Slinkys end-to-end using the 67-foot wire measurement, you'd have enough wire to circle the Earth more than three times.

The Slinky has even been to space—NASA has used them in physics experiments aboard the Space Shuttle to demonstrate wave motion in zero gravity.

So while 87 feet makes for a catchy factoid, the truth is both more modest and more fascinating: it's a precisely engineered toy that turned 70-ish feet of wire into an American icon.