For the first time, I am going to quilt one of my tops. This one is a baby quilt 45x60. How do I know how much thread to buy to do this? Next, I will be doing twin sized quilts and want to get enough thread, but not way too much. Please help me figure out how to calculate the amount of thread needed for the size of each individual quilt. All quilt tops are my own designs so no patterns to follow. Thanks ahead of time for any advice.

It is really hard to calculate how much thread for quilting. Depends on if SID, stippling, meandering, or other FMQ pattern. I would suggest buying 2 spools of color thread. You will be amazed how much thread FMQ takes.

I agree! If you do FMQ you can easily use several bobbins!

This all depends on how densely you are quilting. For a twin, I've gone through as many as 11 bobbins full of thread. Generally, I do not go through more than 1 - 800 meter (larger sized) spool. But I always buy a second spool, just in case. I use Guttermann Machine Quilting 100% cotton thread on all my quilts. My machine seems to like it.

Even with a medium density of FMQ quilting for a twin sized quilt, I very rarely go through 500 yards for the top....But I also generally also use a different thread for the bobbins depending on the color of my backing. For the bobbins, I often buy the large cones of thread and they seem to last forever! I try to buy them in colors I know I will use over and over again (dark greens/blues/tans, etc). I do more matching on the top colors.