What Is A Black Spider With Red Spot On Back?

I don't know, but I found 2 in my house! One in the toilet and another right on top of my dining room table. These were not black widows because the red spot was on its back, not on the underside. And it was not an hourglass shape.

I'd like to know what it is and if it is poisonous.

Ill take a guess of a black widow
there extremely dangerous. So be careful

It can still be a black widow even if the red spot is not a hourglass shape.

Black widow

If the spot is on its back and not on its belly, its probably a bold jumping spider (phidippus audax). If it is a jumping spider it will also be hairy and run very fast. It will have metallic green or blue fangs, as all spiders from the genus phidippus do. If your spider fits this description, there is nothing to worry about, as they are very friendly and their bite is comparable to a bee sting.