Most patterns will tell you what gauge (tension) you need in order for your finished piece to work up to the measurement listed in the pattern. For example, for my Taylor Newsboy Hat, I gave the following gauge of 14 hdc and 12 rows = 4" using an I hook. To work up a swatch, chain a number larger than 14, I would suggest maybe 20, that way you can get a better read on how many stitches you get in 4" without having to count the starting chain which can skew your count. Then, using the stitch given in the gauge, in this case hdc, start working back and forth in rows until your swatch measures 4" tall. Now, take a tape measure and see how many sts you can count in 4". If you work up a swatch and get more than 14
There will be times where a pattern will say that the gauge is not important. Usually those patterns use measurements to guide you through the pattern instead of a specific number of stitches.
Ok! Now on to the experiment!
Ana of Accessorise, 14 hdc x 9 rows
Emily of Em's Corner, 13 hdc x 10 rows
Danyel of Danyel Pink Designs, 12 hdc x 10 rows
Jenny of Ella Bella Bows, 15 hdc x 10 rows
Michelle of From Home, 14 hdc x 10 rows
Liz of EW Designs, 14 hdc x 10 rows
Sonya of Blackstone Designs, 13 hdc x 11 rows
Cassie of Scarlet's Corner, 13 hdc x 10 rows
Crystal of Crystalized Designs, 13 hdc x 10 rows.
They all used Red Heart Soft yarn and an I hook. Their gauges were anywhere from 12 to 15 hdc in 4"!! That is a HUGE difference! 3 extra stitches for every 4 inches adds up quickly. The number of rows were very similar, most having 10 rows in 4" with only one having 9, and one 11.
Alright! Now that you have seen the difference, are you ready to whip up your own gauge swatch and see what happens? Remember, even the same hook with different yarn can alter your gauge. Work one up today and comment below with your results! Which Designer did you match up with? Is yours completely different than what you see above?