WPI - HELP! Explain

I’m writing my patterns in Portuguese and there isn’t much standardized as far as yarn or even terminology in Portuguese. Since most people are probably not going to have the same yarn available as I do in the U.S. I want to describe the yarn with the WPI (wraps per inch) method, which I believe is a good one for figuring out weight.

QUESTION: when describing WPI, is there ONE needle size used to measure WPI, or is it a smaller needle for lighter yarns like fingering than for worsted or bulky?

I’ve never really used this method for determining yarn weight myself but need to learn because sometimes a yarn is described as something and I think it feels like a different weight.

Wraps per inch doesn’t depend on the needle size. You can even wrap the yarn around a ruler. You’re not going to measure the length of yarn that wraps around the needle (or ruler or even special wrapping tool), you’re just going to measure how many times the yarn wraps around until you have one inch of wraps. That number will be the WPI.

WPI is just wrapping around a needle, a pencil or a ruler and counting how many wraps in one inch; it doesn’t matter how thick the item is that you wrap it around.

Gauge and needle size might be a better way to describe the yarn needed because wpi can be deceptive. A thin yarn that’s very fuzzy will wrap as a lighter weight yarn, but in reality it’s knit at a looser gauge on larger needles, because the fuzz helps fill in the sts. Also, wpi is more of a range than an absolute and people may not be able to get exactly the same wpi as your yarns do, and if a person stretches the yarn as they wrap, it’s going to appear to be a thinner yarn than it really is.

Thank you both, that made sense!!!

Very good point about gauge and fuzzy yarn, never thought of that.

I don’t understand how wrapping the yarn around any ole thing, such as a pencil, will
render a [U]standardized WPI measurement[/U]. ???

[COLOR=Blue]This is what I use (it’s never failed me when I am substituting one yarn for another)
…and it’s available at Knit Picks and WEBS, and prolly elsewhere.[/COLOR]

[COLOR=Blue]Here is what WEBS says about the tool:[/COLOR]

[B]Nancy’s Knit Knacks WPI Tool [/B]

                        "Our WPI Tool is a handy device for all fiber artists who want to  measure their fiber's "wraps-per-inch". Two yarns that have the same WPI  can be exchanged. This is important if you are trying to substitute one  yarn for another for a given pattern. The WPI Tool is made from birch  hardwood and measures 5" in length x 5/16" diameter. There are markings  for up to 3 inches which allows you to calculate a more accurate average  WPI on certain hairy yarns. There are also 1/2 inch marks. All markings  are laser etched into the wood and will not wear off."

How nice to see the precise tool. This makes doing wraps much easier because it also has a notch for holding the end of yarn in place. WPI is an approximate measure of how wide the strand of yarn is. You could use a pencil, a ruler, or a coffee can, as long as you’re able to measure an inch or two along the length. It’s more accurate than trying to measure the width of one strand and as you say, it hasn’t failed you yet.

It’s a handy little tool, but a ruler has the measurement marked out too. The diameter/width of the item doesn’t really matter, you’re measuring the thickness of the yarn strand.

It works to use anything because it would be the same as putting pieces/strings of yarn flat side by side for an inch and then counting how many pieces of yarn you have.
You are measuring the “thickness” of yarn … how many single pieces of yarn does it take to make an inch :slight_smile: