Peaches, my specialty area of relic-study is pre-1900s projectiles, as my posting-name indicates.
Doing the math... 14" circumference divided by Pi (3.1416) equals 4.45" diameter. So, your ball's diameter is correct for a Revolutionary War / 1812-War "12-Pounder caliber" cannonball. (Civil War ones in that caliber were slightly larger, about 4.52"-diameter.)
However, as other folks here have already mentioned, that caliber of 12-pounder caliber Solid-Shot cannonball weighed 11 pounds 14 ounces (RevWar) to a maximum of 12 pounds 4 ounces (Civil War). Typical household bathroom weighing-scales are notoriously inaccurate. You'll need to weigh your ball on a precision scale, such as a Postal Shipping scale. If it weighs more than the weight-data given above, it is not a cannonball.
Meanwhile, I will say that it "has the correct look" for a corroded cast-iron RevWar cannonball... and I hope for your sake that its precisely-measured weight turns out to be correct for that (tentative) ID.