Fluid Effects > Edit Fluid Resolution
 
 
 
Rebuild Initial State

Turn this option on to reset the initial state after changing the fluid resolution, saving the dynamic grid fluid properties in the initial state cache file. For information on initial states, see Fluids initial state

X, Y Resolution

Set the X and Y resolution, in voxels.

3D only:

Z Resolution

For 3D fluids only, set the Z resolution, in voxels.