Gauge in knitting

I am having a hard time getting a 4 stitches to inch in gauge to start my project. I am doing double yarn for a poncho for my grand daughter. I get 3 1/2 or 4 1/2 but not 4. I am doing this in garter stitch. So can anyone help me with this? This I have worked on it to knitting is no fun right now.

I’m assuming you’re measuring sts/inch across the middle part of you swatch to give you the most accurate measure.
You could go with the needles that give you 3.5sts/inch if you like the fabric at that tension and make the poncho a little smaller either by subtracting sts or by making the next smaller size. Or figure out how wide the poncho is going to be if you use 3.5sts/inch and see if that would be ok. Perhaps a little larger is something that would last another year?
Happy Thanksgiving to you!

Where are you measuring from? You need to knit your swatch for a few inches and measure in the middle. If you measure from the first row after the cast on, your numbers are going to be off. That first row is always tighter than the rest of the knitting. Your numbers are also going to be off if you measure at the edges.

I have taken your advice and going to put in to practice. I will back with you about gauge.
Gerri 25

I want to thank everyone for their help with my problem with gauge. I did the ponchos with single yarn and a larger needle. I learned a lot about gauge.