I have uploaded a free sewing pattern for kids' size 11 years night pants with elasticated waist at this link. Download the PDF pages and assemble the pages as shown in the picture below.
Cut 2 pieces each for front and back.
Seam allowances are already included in the pattern:
1.5 inches at the waist for casing for the elastic.
1.5 inches at the bottom for hem allowance.
0.50 inch for the side seam.
0.25 inch for the crotch seam and inseam.
I will try to post the pattern in other sizes too.
You can find lots of free PDF printable sewing patterns on this page on my blog. You can download and use them to create your own clothes.
You can also click the Free Sewing Patterns Page at the top of this blog page (under the blog title) to find more free sewing patterns.
Click the below links to browse through all the pattern drafting and sewing tutorials on my blog.
Happy sewing!
---Flora