How long does cat labor take?

It depends on the number of kittens. If we think she's pregnant and we can catch it in time, we can get an x-ray to know how many kittens there are and, that way, how many to expect. If she's supposed to have six and you've had five, you know you should be waiting for one more, which is important to know because sometimes you don't know when she's done. That's part of what guides that process. On top of that, cat labor depends on the number of kittens you have because if you have an hour or two gaps between kittens, it could span longer than if she's pushing them out without any breaks. I would say it probably lasts a couple of hours to half a day, but sometime in that range, ultimately depending on how many kittens there are.