How I can create seat for this bar stool legs that have a swivel base?

I would cut a circle out of plywood and then cover it with batting and fabric and screw it on to the base. That would be the easiest way to go.

Veronica: maybe this can help

https://www.youtube.com/watch?v=ZATTgaF_pXQ

I agree with Kim! Definitely cut a circle out of wood. You could refinish it of upholster. If you need help upholstering, here is my post on how to upholster around a curve:

https://karupp-did.net/re-upholster-with-white/

I would make a round template out of cardboard to size the seat. Use the template to cut a circle out of 1/2" or 3/4" plywood. If you want a softer seat cover with a foam, then batting, then fabric. Staple the batting and fabric from underneath. Lay down the cushion face down and place the stool on top swivel on top of the cushion centering it. Four screws to fasten the swivel to the cushion

https://www.hometalk.com/search/posts?filter=upholster%20stool

You could cut a simple plywood circle and upholster it really simply. Choose your fave fabric!

The sell wood circles that look just like a seat at Home Depot in the lumber area. You could DIY it into a seat.

here is a place that sells the seats that may help you out

https://foter.com/replacement-seats-bar-stools

Hello there,

Cut out a Circle of timber and fix it to the top using the holes provided from underneath. Hope that helps.

cut a shape that you like and upholster that with nice fabric or faux leather

Cut a round piece of wood and attach to the top with a cushion

Cut a piece of plywood the size you want then staple some backing and cover and staple it on the screw it to the metel and your seat is made

You can also buy round pieces of wood from craft stores in the unfinished wood section that would work for this.

Cut-out a circle in wood add some foam and cover it. You screw into the wood from the bottom to attach it to the frame.

Your local home improvement store will have round wood shapes perfect for this. You can stain them or add cushioning and upholster.

Just make sure that the screws you use are shorter than the thickness of the wood circle. Don't want anything coming up and poking the sitter.