Most washing machine vibration noise in an apartment is a setup problem - transit bolts left in, a foot that is not carrying weight, a single wet bath mat on spin - and the free checks fix more of it than any purchase does. When the setup is right and the floor still shakes, four anti-vibration pads under the feet are the best value fix in the whole floor category.
Dog nail noise and running children are both impact noise, and both travel along predictable paths, so the fix is dense coverage on the routes they actually use rather than a rug in the middle of every room. Here is how to map those paths, why the rug pad matters more than the rug, and what to say to the neighbor below.
Interlocking foam tiles reduce impact noise a little, in the squares where you actually lay them, and nowhere near as much as the listings imply. Almost every number printed on a puzzle mat listing measures something other than what your downstairs neighbor hears, and no tile we have found publishes an impact figure for itself at all.
Renters can soundproof a floor, but only with the loose-laid, removable half of the category, and the most effective product in that category is the one a lease normally rules out. Here is the reversibility test that settles most purchases, the clauses to go and read in your own lease, and an honest accounting of what the money buys.
These are not three grades of the same product. They are three different jobs, and only one of them is genuinely available to most renters. Here is which of the three to buy first, and the one measurement that explains why.
Training at home is acoustically the loudest thing most renters do, and a dropped weight is the one noise no floor you can lay will absorb. Here is the order that actually works: technique, then equipment, then siting, then the floor.
Underlayment is the most effective floor product in this whole category and the one most renters cannot use, because it goes under a floating floor you install yourself. If you are laying one, here is how felt, cork, rubber and foam compare on delta IIC and on cost per square foot.
Partly, and almost certainly not for the reason you bought them. Three different questions hide inside this one search, they are settled by three different tests, and the number printed on the box answers the least useful of them.
You are almost certainly not stomping. Ordinary walking is audible through most apartment floors because of how they were built, and the three fixes that help most are free or close to it. Here is the order to do them in.
Most people searching this are not trying to get quieter. They are trying to stop being the problem for the apartment below. That changes which product helps, and makes the rating printed on most floor mats irrelevant.
Every mat in this category was built for drummers, and every number printed on the box measures absorption, not impact isolation. Here is what a felt tile can and cannot do for the neighbour below, and how to pick one anyway.
A window AC is a hole in your wall with a machine in it. The street noise comes through the gap, not through the machine, and the accordion side panels that shipped in the box are the leakiest part of the whole installation.