How long will it take for a toilet to unclog itself?
If normal materials like toilet paper and feces clog your toilet, your toilet will eventually unclog itself. It can take as little as an hour for the unclogging to happen or as long as 24 hours.
If you have a second bathroom that you can use, then yes leaving a clog overnight is fine. If you only have one toilet in your home, you should strongly consider alternative methods for getting out the clog.
The most important thing you can do in this situation is not to flush a second time. Forcing the toilet to flush again releases gallons of water into the toilet bowl and will cause an overflow.
In case the matter is more serious plungers do not work anymore and at this point of time plumbers come up with a much stronger instrument known as the toilet auger or toilet snake.
How much will it cost for a plumber to unclog my toilet?
The national average cost to unclog a toilet is $200 to $700, with most people spending about $350 for a plumber to use an electric auger to clear the toilet drain clog and test the system.