http://www.craftpassion.com/2014/09/lunch-box-bag.html/2

Lunch Box Bag

Difficulty: Avid Beginner with some sewing experiences
Finished size (including handles) : approximately 6″ (W) x 12 1/2″ (H) x 4″ (D)
Update: height of the bag itself (without handle) is approx. 7″
Download: Lunch Box Bag Pattern

Materials:
Make: 1
1. Fabric, for bag – 10 1/2″ x 19″
2. Interfacing (medium weight) – 10 1/2″ x 19″
3. Fabric, for lining – 10 1/2″ x 19″
4. Fabric, for drawstring cover – 2 pcs. of 10 1/2″ x 6″
5. Fabric, for handles – 2 pcs of 3″ x 14″, or use webbing tape 3/4″ width 2 pcs of 14″
6. Drawstring cord, 2 pcs of 24″
7. Drawstring beads or stopper, 2 pcs. optional.

Tools:
1. Sewing machine
2. Sewing kits
3. Pencil or Erasable fabric marker
4. Ruler
5. Scissors or roller cutter
6. Cord threader
7. Iron

Seam Allowance: 5/16″ (included in the pattern), otherwise as indicate.

Note: If you are using canvas or upholstery fabric for the bag, you may omit the interfacing.

Gather all the materials and tools needed as listed above. Download the pattern sheet for the dimension to cut.
Cut fabrics according to the pattern sheet.

Fuse interfacing webbing to the wrong side of the bag fabric with warm iron. Make sure it is properly fused and no trapped air bubbles between the fabrics.

The bag fabric with interfacing attached. Set aside.

Fold the lining fabric into halve with right side facing each other. Sew both side edges with 5/16″ seam allowance.

Pinch the vertical center lines of both front and back piece, open up the lining, bring center to side and seam lines to center. Align the front and back seam lines, the bottom reverse triangle must be perpendicular to the seam lines.
Measure 4″ horizontally across the bottom of the triangle of the front corner and sew. Repeat the same at the other corner of the bag. [Update: it is not 4″ from the tip of the triangle, it is 4″ perpendicular to the sewn line, which is also the length that you are going to sew.]
Cut away the extra with 5/16″ seam allowance.

The lining should look like this after the seams returns to it’s side position.
Set aside.

Fold the long edges of the handle toward the center, leaving about a 1/4″ in between them. Press with iron to set the crease lines.
Fold it into halve and press with iron. Sew a line near the edge on both side.
Repeat the same to the second handle.
Set aside.

Place 2 pieces of drawstring fabric with right side facing each other. Sew the short side of the edges till the 1 1/2″ marking.
Press seam open.

Top stitch about 1/8″ from the seam line at both sides.

Double fold the top edge to the wrong side to make a 5/8″ pocket for the drawstring. Top stitch 2 lines.
Set aside.

Fold the bag fabric into halve, fold the bottom 2″ up. Sew the side with 5/16″ seam allowance.

Turn the bag right side out, expand the base of the bag to have 4″ on the sides and roughly 6″ on the front & back.

You may press it flat like this by simply push the bottom into the bag.

Attach the handle 4 1/2″ apart (inner space), stitch it on about 3/8″ from the top edge.
Repeat the same to the other handle.

Turn the drawstring fabric to the wrong side and slip it onto the bag, with drawstring pocket facing down.

Insert the bag and drawstring pieces into the lining piece.
Align side seams. Change the facing of the seam allowance if needed to avoid thick fabrics on the same spot.

Sew around with 1/2″ seam allowance, leaving a 3″ to 3 1/2″ opening for turning right side out.

Turn the bag right side out from the opening.

Press the top seam neatly and sew 4 lines within 1 inch from the top edge.

Thread drawstring cord and install stoppers (optional) to complete the lunch box bag.
Install name tag to bag if you wish. I used faux nubuck leather aka washable craft paper or kraft paper fabric, you may use felt as an alternative. I stamped the grass and dragonfly by using StazOn Multi-Surface Inkpad, Stone Gray.
You may lay the bag flat when not in use.