My way of doing math…buy this.

Circumference is 48". The object is round which means the paper in the bag has to be a little more than 48" to surround it. A 24" wide and tall bag has 48" of paper because it is folded on half. So I would use a 25 inch wide and tall bag or maybe a little more depending on closure type. . Is this correct? IDK I am not a mathemetician.

lucille is right, so you'd need something larger than 16x16x16".

What kind of bag are you thinking of? I use 13-gallon Hefty clear recycling bags to store a lot of things, they are 23”x27”.

^Same as bpath. I’ve used both 13 and 33 gallon bags.

Take the diameter, or two times the radius, and add a couple of inches.

Pi X diameter = circumference. Pi is 22/7 or 3.14. So bag needs to be at least 16X16.

When I moved into my first house and wanted to put a mulch circle three feet out around a tree, I needed to know how much edging to get. Aha, high school geometry finally useful. I would need 22’7”. But edging came in 20’ rolls at the hardware store. Oh well, close enough. At least I didn’t guess wildly and come home with half a dozen rolls. Now I just multiply (or divide) by 3. ”Close enough for goverment work”, just not for kitchen planning.

(my DSIL taught me a trick for C to F temperature conversion. Double it and add 30. 32 if you want a little more precision. Don’t use it in the science lab, but it helps me know if I will need a sweater.)

"Sorry @sushipup2 and @clt3, that only works for a flat circle and does not take into account the thickness of the ball, which is also 16". Lucille's approach is a good one.

It needs to be a cube shape with at least 16X16x16. I was taking into consideration that it is a sphere, not flat.

I missed the "sphere" in the OP.

Oops - just realized the OP does not mention a base - I was picturing a topiary in a container 🙃

https://a.co/d/7LwvNlM

@clt3, where might one find cube shaped plastic bags? And you only said 16 x 16 in your original post.

@foodonastump, that’s a brilliant idea!

Bed linens often come in zipper bags that are square or rectangle, perhaps you have one in the house?

I must say that I have no idea what it going on in this thread and I sort of like math. Maybe I am confused because I did not see a reference to 16x16 anywhere. Nor was height mentioned. With all that said, I would just google and find a Christmas tree storage bag that works if it is a large planter needing protection.

Thank you for all the input. I realized that I had (somewhere) one of those huge vacuum bags for storing big comforters, and my boxwood spheres - both of them!! - fit perfectly. Yay! Can't actually vacuum the air out, but that doesn't matter. It closes properly otherwise, and keeping the dust off these is what I wanted.

Again - thanks for chiming in - I appreciate it! =)