If Biden wins 60% of pledged delegates going forward, he'd clinch around late May.
If he wins 65%, he'd clinch around early May.
Even if he wins most states, this could take a while
That doesn't accelerate things as much as you might think. Let's say Biden wins 85% of FL's delegates and 65% of all other delegates. Still takes till late April to hit the magic number.
But Democrats structure their nomination contest with proportional rules that make it very hard for someone to actually clinch till late