What swing speed do you need to hit 250 yards?

It depends on whether you mean carry or total.

To carry 250 yards in the air, TrackMan’s driver optimizer puts you at roughly 101 to 105 mph. At 100 mph with an upward 5-degree strike the model carries 247 yards; at 105 mph with a level strike it carries 251. Those are optimized numbers, so a typical amateur strike needs a few more mph.

To reach 250 total, with roll on a firm fairway, the same charts show 90 to 97 mph getting there under good launch conditions.

For scale, TrackMan’s PGA Tour average is about 115 mph and 282 yards of carry. If you carry 250, you are already faster than most amateurs, and a firm, higher-compression ball will hold its speed for you better than a soft one.