Ok so I know I'm not the first to come up with this idea of comfy, flannel pants but hey, here's a free tutorial on how to make them. I make mine super wide legged (because it rocks) and about 6" too long so I can let out the hem as my kiddo grows.
Ok so first off you need to measure the kid. Waist, inseam, length and rise (this is the measure of the back where the pants will sit to between the legs).
My kid has a 19" waist, 18" inseam and 24.5" hip to heel measurement and an 8.5" rise.
Then we need to make the pattern.
Take the waist measurements and divide by 4, then add 1". Make a rectangle out of this that's the length of the rise. Add 2" to the rise for SA (seam allowance).
Add two inches below the rise to the "leg". then draw a shape similar to what I have to connect the leg width and the waist width.
Wah Lah! There's your pattern. The long side opposite the rise notch is to be cut on a fold. You'll need to cut 2 of these out of your fabric with the leg the length plus 2" for SA or more if you want to hem them up. You need and a piece of elastic 1" longer than the waist measurement. I tend to cut my pieces on an angle to make whopping large legs. I think it looks cool, you can cut it narrower if you choose.
After you cut the fabric open it up and stick RST (right sides together) and you'll pin along the arc of the rise only at this point.
fold the pants so the seams are together still RST and pin the legs all the way around. I make this one run with a straight and then zig zag with a back and forth stitch on the crotch to reinforce.
After this is sewn remove the pins and fold over the bottom 1/2 edge of the pant cuffs and stitch it. Then fold it over again to match your hip to heel length. Sew this near the top where they meet not at the fold if you have a larger hem because it'll come down and trip your kid. It's not as funny as it sounds.
Fold over the waist 1/2" and sew, then fold over another 1" and sew all but the last 1", use this to thread your elastic through. A quick way to do this is to pin your elastic to a safety pin and pull the pin through. Sew the ends together then sew your hole shut. Clip off the stray threads and you're ready to lounge!!!
If you like the pants but need more info/instructions please leave a comment and I'll comment back with whatever help I can give! I plan on making more of these for my baby and my girls so check back!