Round bottom is a nice feature not only for bag bottom but also for a cylindrical pouches and bags. Here is how!

Step 1. Make a card board template for a half circle. Make sure that you do this very neatly. Fold the fabric in half, secure it with pins. Draw the half circle with the fold as the diameter.

Step 2. Cut the half circle along the line you have just drawn. Open it flat. Divide the circle in 8 place makings. There will be eight markings equidistant to each other at the rim of the circule (see picture).

Step 3. The with of the fabric for the side part is determined by the circumference formula. Make sure that the diameter d, is the actual diameter of the template circle minus 2cm (1cm seam allowance). You would most likely to get a value with lots of decimal places, so to make your life simple round the number to the nearest whole or 1 decimal number. When you know the circumference add 2cm for the seams (1cm seam allowance again). You would then cut one sheet of fabric with the width calculated and height of your preference.

Step 4. Sew the seams and fold the piece in 8 equal parts and mark the position. You should now have 8 markings (including one sewn section) equidistant to each other.

Step 5. Match the markings on the circle and the side parts and secure it with pins or clips.

Step 6. Sew the edges around the circle. Make small notches on the side panel fabric to ensure the markings are kept matched as the fabric would feel stretched.

Step 7. Cut the seam off to 5mm.

Step 8. For pouches that are going to be used for the exterior part, once the work is turned right side iron the sewn edges in few sections. All you need to do is to gently place the edge of the steam iron for 1-2 seconds to tidy it.

Here is what I made earlier!