Mine take about a year!
But you will be amazed at how many tiny tadpoles just disappear. I start out with hundreds and end up with maybe 1-2 larger ones. Sometimes mine overwinter and don't become frogs/toads until the next summer.

Just try to collect as many as you want and work on your pond.

depends on what kind of frog/toad.

The Pacific chorus frogs I have here just take a few weeks but bullfrogs can take two years.