Sew a Backpack with adjustable straps :Sewing Tutorial

how to sew a backpack

How to sew an easy backpack with adjustable straps 

Step 1 Cut out the fabric pieces for the bag

You need two front pieces from the outer fabric and lining in the  dimensions – 19 inches wide and 17 1/2 inches long from the lining fabric and 19 inches wide and 18 1/2 inches long from the outer fabric. 

Cut out one outer fabric 19 inch by 18.5 inch and lining 19 inch by 17.5 inch

You also need two back pieces from the outer fabric and lining in the  dimensions – 12 inches wide and 17 1/2 inches long from the lining fabric and 12 inches wide and 18 1/2 inches long from the outer fabric.

Cut out one outer fabric 17 inch by 12 inch and lining 18.5 inch by 12 inch

And interfacing for all the pieces, which goes without saying.

Mark two oval shapes on the outer fabric and the lining fabric for the bottom of the bag. Fold the fabric and mark as given below. Cut it out.

8 inches by 5 3/4 inches Outer and lining ovals

You also need to cut two flap fabric pieces – one from the outer fabric and another from the lining. (Instead of the lining fabric you may want to use outer fabric for this as this fabric is visible) 

flaps for the back pack sewing tutorial

 

cut 2 backpack flaps - 9 inches by 7 inches

You also need 4 straps

For the straps cut fabric in these dimensions

2 straps – 36 inches by 3 inches 

2 straps – 5 inches by 3 inches

cut 2 straps - 36 inches by 3 inches and 2 straps 5 inches by 3 inches

And one extra fabric piece of the outer fabric – 3 inches by 12 inches for attaching the flap and the straps

Hardware needed – 2 sliders, 2 rectangle rings, a pair of magnetic snaps or Velcro.

Step 2 Make the adjustable straps.

Keep the long side edges of the strap pieces (right sides) together and sew with a 1/4 inch seam allowance, forming a tube.

sew the adjustable straps for the backpack

Turn the tube right side out with whatever means you usually use. With long tubes I simply use a needle and thread method.

turn it rightside out

Turn it rightside out.

the tube that will be the straps for the backpack

Adjust the seam to the back and press in place.

Turn the seam of the backpack straps to the back and press

Top stitch the edges of the straps to make them firm.

Top stitch along the edges

Step 3 Assemble the straps.

You need to get 2 sliders, 2 square rings for making the adjustable straps.

Get the sliders and the rings

Thread the rectangular rings with the short straps.

Keep straps curved on the rings

Insert one end of the long strap through the slider as in the picture below.

pass the straps through the slider

Thread the lower end of the strap with the rectangular strap.

Now turn the strap upside down; Thread the lower edge of the strap through the bar of the slider from top to bottom to the inside – see the picture to be clear.

Turn it up and stitch in place

Sew the edge across.

Sew the strap

This is what you get.

Adjustable straps for the backpack bag

Step 4 Prepare the flap.

Take the two flap pieces and keep them right sides together.

Sew along the edge with a 1/4 inch allowance.

Sew the flap pieces

Clip all alomg the seam allowance.

clip the edges

Turn it right side out. You need to attach a magnetic snap or velcro to close your back pack at the lining part of the flap.

Attach it from the inside of the lining – so that it will not be visible from the outside. (Actually if you are attaching velcro you should do this before assembling the flap)

how to sew a back pack with adjustable straps

Keep a washer as well as a small piece of fabric in the back where you attach the snap to give it more strength .

Attach magnetic snaps

Top stitch along the outer edge of the flap to beautify it.

Edge stitch the flap

Step 5 Assemble the back piece with straps.

Keep the straps and the flap on the back piece (outer fabric piece) as in the picture below.

Assemble the flap straps and the outer piece

Keep 3 inch wide and 12 inch long outer fabric piece on top of the joint near the flap and top stitch in place. Sew along the bottom edge also keeping the straps all together for the time being. 

Place a 3 inch by 12 inch piece over the joining place of flap and straps

Step 6 Make the bag body.

Sew the fabric pieces for the lining together to make a tube.

The 17 1/2 inch sides are joined for the lining bag and the 18 1/2 inch sides are joined for the outer bag.

Join the bag pieces at the long sides - make outer bag and lining bag Make a tube with the pieces

Now attach the oval piece to the tube as the bottom edge.

attach the bottom oval piece how to sew a back pack with adjustable straps how to sew a back pack with adjustable straps

Do these steps for the outer fabric as well.

backpack

This is how the outer bag looks on the back with the adjustable straps.

backpack bag

You now have two bag pieces – one of outer fabric and one of lining.The lining is a little shorter than the outer bag.

Step 6 Assemble the bag body.

Keep the outer bag rightside out. Keep the lining bag inner side out.

Insert the lining bag body inside the outer bag.

Insert lining bag inside the outer bag ; fold the top edge and sew in place
Insert lining bag inside the outer bag ; fold the top edge and sew in place

Now just turn the outer bag top edge to the inside and sew in place with your sewing machine.

Step 7 Attach the other part of the magnetic snap on the front of the bag.

Keep the flap closed and see where the snap should be attached.

Attach magnetic snaps to the front of the bag
Attach magnetic snaps to the front of the bag
BACKPACK sewing DIY

Related post : Easy to sew drawstring backpack ; Names of all kinds of bags

Updated on August 29, 2022 by Sarina Tariq

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