As you will note in the equation on the page I shared, time dilation is only a function of how fast a body is moving with respect to the speed of light. That is the time dilation due to relative velocity between two bodies. What I believe you are now asking for is time dilation caused by a clock experiencing a gravitational acceleration. http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/gratim.html#c4
In using this equation "g" would be the gravitational acceleration induced by the black hole, and "R" would be the radius to the black hole's event horizon.