Hydraulic Cylinder Volume Calculator
Hydraulic cylinder volume uses V = pi r squared stroke. For a cylinder with bore diameter 4 in, rod diameter 2 in, and 10 in stroke, extension volume is 125.66 cu in (0.544 US gallons) and retraction volume is 94.25 cu in (0.408 US gallons). Calculate hydraulic fluid volume and rod displacement below.
Calculator
Bore side and rod side volumes
Piston bore and fluid displacement
This tool finds fluid volume in hydraulic rams. It gives extension volume. It gives retraction volume.
Rod volume and extend versus retract stroke
Extension volume is V = pi times (bore / 2) squared times stroke. Retraction volume subtracts rod volume. The difference gives the volume displaced by the rod.
Frequently Asked Questions
What is the formula for hydraulic cylinder volume?
For the bore side (full extension), the formula is V = π × (bore/2)² × stroke. For the rod side (retraction), the formula is V = π × [(bore/2)² − (rod/2)²] × stroke. Our hydraulic cylinder volume calculator runs both formulas simultaneously.
What is the difference between bore and rod side?
The bore side refers to the full internal area of the piston chamber, which completely fills with fluid. The rod side is the opposite end of the chamber, where the physical steel rod pushes through the seal, taking up valuable volume space.
How do you size a hydraulic pump using volume?
Once you know your total cylinder volume in cubic inches, you can calculate required pump flow. The formula is Flow (GPM) = Cylinder Volume (in³) × Cycles per Minute ÷ 231. This ensures your pump provides enough fluid fast enough.
Why is my retraction stroke faster than my extension stroke?
Because the metal rod occupies space inside the cylinder, the rod-side chamber requires significantly less fluid to fill up compared to the empty bore-side chamber. Less required fluid means the pump fills it faster, resulting in a quicker retraction speed.
Can I use this tool for pneumatic cylinders?
Yes! The internal geometric math for a pneumatic (air) cylinder is identical to a hydraulic (liquid) cylinder. However, because air compresses and liquid does not, actual real-world force output will differ.