Pneumatic Cylinder Force Calculator
Push and pull force of a double- or single-acting air cylinder from bore, rod and pressure (bar, psi, kPa or MPa) — or the bore or pressure you need for a load — with a load factor, spring return, air consumption per cycle and per minute including tubing, piston speed and a force table for every standard ISO bore.
How it works
F push = P × π D²/4 (− spring force on a single-acting cylinder) · F pull = P × π (D² − d²)/4 · usable force = theoretical × load factor · bore needed D = √(4 F ÷ (load factor × π P)) (+ d² inside the root for a pulling load) · pressure needed P = F ÷ (load factor × A) · free air per cycle = (A push + A pull) × stroke × (P + p atm) ÷ p atm (+ tubing volume) · consumption = free air per cycle × cycles per minute × number of cylinders
An air cylinder turns pressure into force through its piston area: at the common 6 bar (about 87 psi), each square centimetre of piston gives roughly 60 N. On the retract stroke the rod covers part of the piston face, so a double-acting cylinder pulls with less force than it pushes — noticeably so on small bores with thick rods. A single-acting cylinder extends on air and returns on a spring, so the spring force is subtracted from the push and is the only return force. The calculator works three ways: force from bore and pressure, the standard bore you need for a load, or the pressure you need with a given bore. Real cylinders lose 5–20% to seal friction and need margin to accelerate the load; the load factor covers this (around 70% for moving loads, 80–90% for clamping and holding). Air consumption comes from the swept volume plus the tubing between valve and cylinder, converted to free air at atmospheric pressure — the figure that sizes the compressor and valves. A table compares every standard bore from 8 to 320 mm with its ISO rod, and a second shows the force at other pressures.
Worked example
A 63 mm bore, 20 mm rod double-acting cylinder at 6 bar: piston area π × 63² ÷ 4 = 3,117 mm², so it pushes with 3,117 mm² × 0.6 N/mm² = 1,870 N (191 kgf) and, on the 2,803 mm² annulus, pulls with 1,682 N. At an 80% load factor that is about 1,496 N usable push. With a 200 mm stroke the swept volume is 1.18 L per cycle, or 8.2 L of free air at 7.013 ÷ 1.013 times atmospheric — 164 L/min at 20 cycles per minute. To lift 1,000 N at 6 bar with a 70% load factor, Solve for "Bore needed" gives a 55.1 mm minimum, so a 63 mm cylinder.
Sources: ISO 15552 — Pneumatic cylinders with detachable mountings, 1,000 kPa series, bores 32–320 mm · ISO 6432 — Single rod cylinders, bores 8–25 mm
Frequently asked questions
How do I size a cylinder for a 1,000 N load?
Choose “Bore needed”, enter 1,000 N, your pressure and a load factor. At 6 bar and 70% the theoretical force is 1,429 N, the area 23.8 cm² and the minimum bore 55 mm, so the calculator picks the next standard size, 63 mm.
What pressure do most shops run?
6–7 bar (90–100 psi) at the compressor; allow 0.5–1 bar of drop through hoses and valves, so calculate at 5–6 bar at the cylinder.
Why is the pull force lower than the push force?
On the retract side the rod takes up part of the piston face, so the air acts on a ring (annulus) of area π(D² − d²)/4. A 32 mm bore with a 12 mm rod pushes 483 N but pulls 415 N at 6 bar.
How does a single-acting cylinder differ?
Air extends it and a spring returns it. The spring force is subtracted from the push force, the return force is only the spring, and only the extend stroke uses air — roughly half the consumption of a double-acting cylinder of the same size.
Does the tubing really matter for air consumption?
On short-stroke or small-bore cylinders, yes. Each stroke fills and exhausts the tube between valve and cylinder: 2 m of 6 mm tube on each port adds about 0.1 L of compressed air per cycle, which can be a large share for a 16 mm bore.
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This calculator is for educational purposes. Double-check important results before acting on them.