Supplies: 1" wide stiff belting (available at JoAnns), 1/4 yard fabric at least 45" wide, buckle for 1" belt (see sources at the end), pattern paper, thread, scissors, ruler, pins.
Begin by measuring your waist and adding 6" to 8" inches to the length (I tend to err on the side of more, especially for a belt using a pronged buckle). Draft and cut a paper pattern 2 times the width of the belting plus 1", by the length plus 1 1/2". So if your waist is 28" (plus a 6" overlap) and your belting is 1" wide, the fabric would be cut 34 1/2" by 3". I like to make a paper pattern to keep on hand for future projects.
Cut the belting the length of your waist plus the extra. So for a the example belt cut it 34" long. You can shape one end to a point if you wish (I'll be covering this in the tutorial).
Using the paper pattern, cut one layer of your fabric. Since my fabric is so thin, I also cut another piece of medium weight fusible interfacing, and used that to add a bit of structure to the fabric so it didn't slip all over the place.
Fold the fabric around the belting, wrong sides out. Line up the cut edges. Using a zipper foot on your sewing machine, sew as close as possible to the belting along the length of the belt.
Gently work the seam to the center of the belting width, and press seam open. Grade the seam allowance. Do not remove the belting yet!
On the shaped end of the belting, stitch along the point being sure to backstitch at the beginning and end. (I found I had to work the belting down a bit, so the point was 1/2" from the raw edge to do this.) Trim the seam allowance and point.
Remove belting and turn the fabric right side out. I found my tube turner came in very handy for this part! Press the belt.
Reinsert the belting into the fabric tube. This will take a little fiddling and carefully easing it over the belting. Be patient.
Turn the open, raw edge inwards about 3/8" and slipstitch closed. Wrap the belt around the center of your pass-through belt buckle, and secure in the back with a doubled thread and whipstiches.
To keep the end in place, you can either make a narrow tube of fabric to make a belt stay. (Cut 1" by 3", sew the long edges together, trim seam, turn right side out and turn in the openings 1/2". Slipstitch these short ends together to create a fabric ring and slip over the belt.) Or sew a snap set onto the end to keep the tail from sticking out.
Instead of a pass-through buckle, you can also add a pronged buckle and eyelets. Follow the directions as for the pass-through belt up until the instructions to turn under the unfinished edge and attach the buckle. For this variation you will need a buckle with a prong, and awl for making the eyelet holes, and either metal eyelets and eyelet setter (I show two above; one requires a hammer and the other operates like a hole punch) or heavy thread/buttonhole twist to work the eyelets by hand. (Do note that this will be difficult if your belting is very stiff. I recommend using the metal eyelets.)
Being by measuring in 3/4" to 1" from the unfinished edge of the belt. Mark.
Using the awl, work a hole in the fabric where you marked. This sometimes takes a little bit of effort and time if your material is heavy. Set the eyelet according to the directions that came with your setter (or refer to this).
Thread the prong of the buckle through the eyelet. On the back of the belt, fold the free edge around the back of the buckle, turn under the edge 1/4" and whipstitch in place.
On the opposite end of the belt, measure in about 3" to 4" from the point. Mark a series of dots where you want the holes to be for the buckle prong to go through. I generally set mine about 3/4" to 1" apart, and will set 3-4 eyelets. Work a hole at each marking and set eyelets as above.
Sources For belt buckles, you have a few options: covered belt buckles kits are hard to find, but are available with a little digging on sites like Ebay and Etsy, and Vogue Fabrics carries a few kits.
Simple, pass-through buckles are available at fine fabric stores (I've seen a couple at JoAnns occasionally as well), Etsy, Ebay, etc. I tend to find a lot of mine at antique shops (especially if I'm looking for something unique).
Don't forget to look at the thrift shops or even in your own closet for buckles you can repurpose from old belts! The pronged buckle I used in this tutorial was taken from a thrifted belt. For mere pennies, you can find a sturdy buckle in a myriad of finishes!
As I mentioned belting is available at most JoAnns stores; I've found it near the by-the-yard elastic and Velcro tape. This belting is not webbing--it's a semi-stiff buckram strip and usually comes in white only.
I generally buy my eyelets at the local fabric store, but you can find them at most of the larger, online retailers as well. My punch-style eyelet setter was a thrift find years ago, but you can find this readily available in fabric stores too. I find these are a lot easier to work than the hammer-set method, though a bit more pricey. Just be sure to get one that is suited for fabric eyelet setting--not paper!