Do I need bias binding
 

I have two rectangular table toppers, I'd like to use them on my end tables. One table is oval. They are big enough to be cut into an oval shape after I remove the binding. Will I need to make bias binding, I'd like to reuse the original binding if possible.

For any curved edges you really need bias binding.

Bias binding will be much easier to work with on curves.

You will be glad you used bias.

Ditto from me. Bias cut on WOF could work because there is a little bit of wiggle room in it, in other words, it is a bit stretchy. If your original bias was cut on Straight of Grain, then you will fight it every minute and have a lot of wrinkles in it. You won't like it. If in doubt, find something that is rounded or make a practice piece using a really long stitch, called a basting stitch. Turn the piece so that you are working with the curve and pin your binding to it. Don't sew, just pin. Can you work it to your satisfaction? If so, then go for it with the oval. If the binding is wrinkling, either change out your binding, or forget the oval.

Happy Quilting!

Edited to add: Forgot to add, after trying the old binding on the practice piece, just unpin the binding, take out the basting stitch, iron the fabric, and you are back to before the test. No fabric lost.

For sure, bias for a finished look

Bias binding for sure. After you get used to using Bias binding I suspect you will want to use it all the time. It really is so much easier and the corners are always perfect.

Guess I'll have to use bias binding. Does anyone have an idea of how much fabric I'll need to do two toppers approximately 14x20 inches each. I'll never be able to match the binding so will replace both.

I use the chart on this page. It's about 1/3 of the way down the page.
http://www.jaybirdquilts.com/2011/02...rt-2-bias.html