Why does my sewing machine use more thread that the usual

Your bobbin might be in upside down. When you put the bobbin in the bobbincase and pull the thread the bobbin should turn clockwise (on 99% of machines). If its in upside down and turning the wrong way this will happen. All the other suggestions here are good also. Try them and have patience.
Good luck.

When u see loops on the underside of the fabric, the upper thread is not getting good tension. If u see loops on the upper surface, the bobbin thread is not getting proper tension.

This will cure 99% of the tension problems most casual sewing hobbiests see:

1) Remove the top thread from the sewing machine completely.
2) Raise the presser foot
3) Dip a folded piece of washed muslin in a little rubbing alcohol or unflavored vodka & ''floss'' between the upper tension disks with a fold of the fabric. This gets rid of the fluff & grunge & bits of thread caught between the tension disks.
4) Rethread. DO NOT LOWER THE PRESSER FOOT until after you've threaded the tension disks. The tension disks open when the foot is raised, & close when it is lowered (this alone solves 90% of the upper tension issues I've seen).
5) If you've been playing with the tension dial, reset it to 4, which is ''normal tension'' for most fabrics.
6) Fetch up the bobbin thread using the handwheel
7) Raise the presser foot & put the work under the needle. Lower the needle into the work with the handwheel. Lower the presser foot.
8) Holding the bobbin & top thread together behind the presser foot, make a stitch with the handwheel (or the pedal if ur machine can do stitch at a time). Let go of the threads & sew.

If u want the best product ur machine is capable of u will also:
1) change to the correct size & type of needle for the project.
new needle for each project
2) clean out all the fuzzies that accumulate around the bobbin case & under the needleplate
3) oil as prescribed by the manual with sewing machine oil, not 3-in-1 or similar household oils (they gum up & harden) or WD-40 (it is a solvent, not a lubricant)
4) use good quality thread -- less fuzz & slubs
5) use matching thread in bobbin & top (other than for special decorative effects)

Your tension is off. You need to test sew on a scrap of the material you are working with and balance your upper and lower tension (usually a dial on your machine with numbers on it). If you have the manual, look under tension adjustments. It sounds like your upper tension is too tight and your bottom tension is too loose.

I would check the tension on ur machine. It is been a long time since I've sewn much (just getting back into it), but I believe this has something to do with uneven tension. Probably the upper tension is too loose, but I would check both the bobbin tension & the upper tension. They both need to be set to the appropriate tension for the type of fabric & thread u r using. You may also want to change ur needle. And make certain the bobbin is wound evenly & to the correct tension (mostly it may be too loose).

When this happens to me, it is because the bobbin thread has slipped out of the case. Make sure it is tailing into your left hand when you insert the bobbin into the case, and then get the thread all the way down through the little slot. Use a small paintbrush to clean out fuzz from inside the bobbin area every time you change a bobbin.
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u need to check under the bobbin case to see if it is full of lint & brush it out. u also need to check ur needle & make sure it is the right size for the fabric u r using & u should always use a new needle when u start a new project. then ,once u do that check ur top tension & try not to adjust the bobbin tension if u do not have to because it is very delicate. check in ur manual under troubleshooting. here is a web site that may help.scroll down untill u find ur brand of machine.

first make sure the thread isnt jamed somewhere if it isnt try changing the style its on.

Your tensions need to be adjusted. There is a top one and one on your bobbin casing and it will take some experimenting with tightening and loosening both but you should be able to improve the performance with a few turns on both.