Abstract: An integral self-contained drillstring compensator includes at least one high pressure air cylinder, an accumulator, and a compensating cylinder, which are fluidly coupled to one another. The high pressure air cylinders include a compressible gas that is communicable to the accumulator, which has fluid included therein. The compressible gas provides a pressure on the fluid, thereby allowing the fluid to communicable between the accumulator and the compensating cylinder. The fluid causes a cylinder rod within the compensating cylinder to extend and retract from the compensating cylinder, thereby providing compensation during heaves. The drillstring compensator optionally includes a low pressure air cylinder to store a low pressure compressible fluid that communicates with the compensating cylinder.