Whatever the weight of the vehicle is, that's what I based it off of for my car.
I can't hold the entire weight of my car on a single stand but it's fairly close, not that balancing it on there would be possible anyway, but with the other tires on the ground it's taking less weight than that since it's distributed elsewhere. If your car displays the front and rear weights separately on the door sticker, you can get a pretty good idea of how much your jackstand needs to carry. And it'll still be less than that, since the weight will be distributed across two points, whether it'll be a jackstand and a tire, or a jackstand and another jackstand.
Just always make sure to have a jackstand that's a high enough capacity, it's always better to have a jackstand that has a significantly higher rating than you need, cutting it closer is riskier. Please be safe and use common sense and you should be okay. And make sure to always give the car a good shake after you set it on the stands, to make sure it's solid and that the car isn't going to go anywhere.