Remove toilet and replace wax ring!
The first thing to make sure it is leaking from the bottom not that it is leaking someplace else and the water is running down to the bottom of the toilet. Have you tightened the water line that runs from the wall spicket to the bottom of the tank? If all is good, then replace the wax ring.
Sounds like you need a wax ring! ...It's a cheap fix --- just don't drop that heavy toilet!
If you have checked the fixtures inside the toilet then look for a crack in the toilet itself. Then remove the toilet and purchase a wax seal with the funnel attached and replace the one that is there. Shut off the water first and completely drain the tank and sponge out any water that is left. Be sure to have an old towel on the floor because the trap sometimes holds water and will make a mess when you move it. Have a plastic bag handy to catch the old debris such as the old wax and paper towels used for wiping and cleaning.
You need a new seal go to Home Depot get a new toilet seal then take two bolts off of toilet then remove toilet don’t forget to shut water remove all from bowl take whole toilet off scrap off old gasket wax on floor and remove old ring then replace new one then put toilet back and tighten bolts not to tight to crack it and your done