Functionally graded hydrogels with varying composition are useful for applications like tissue engineering, drug delivery, soft actuators etc. Vat-photopolymerization based 3D printers have great potential for the production of such graded hydrogels. However, in-depth studies have not been done on the characteristics of functionally graded hydrogels produced using this process. Also, certain challenges are found to occur in these printers which leads to loss in accuracy when the material composition is changed while printing. Further studies are necessary for overcoming these challenges, so that functionally graded hydrogels can be 3D printed with good accuracy. This study focuses on the geometrical deviations that occur in functionally graded polyethylene glycol diacrylate (PEGDA) hydrogels of varying polymer concentration, produced using vat-based Digital Light Processing (DLP) 3D printer. Studies were done to explore how the printability and dimensions of the hydrogel samples vary with the polymer concentration and printer parameters. The change in dimensions due to swelling was also studied with respect to these parameters. These studies were used to determine the optimal parameters for each PEGDA concentration and a method of giving tolerances on the CAD model was used for correcting the deviations in dimensions. Further, the swelling and compression properties of 3D printed functionally graded hydrogels were studied and compared with the properties of single composition hydrogels. The effect of printer parameters on the properties of the 3D printed hydrogels was also studied.