Calculator

ISO bore for a load

F = p · A, double-acting cylinder. Finds the smallest standard bore (ISO 15552 / ISO 6432) whose extend force meets the given load — with no margin.

Required force F (N)

Working pressure p (bar)

ISO 15552 · Ø50 mm · rod Ø20 mm

Recommended bore: Ø50 mm
Rod: Ø20 mm
Extend force: 1.178 N
Retract force: 990 N

CURRENT STANDARD · TABLE LOOKUP

Validity: Bore up to Ø320 mm

Assumptions: ISO 15552/6432 are interchangeability/mounting-dimension standards, not a force-performance guarantee. F = p*A above is theoretical (no friction); a friction efficiency and air consumption are available as an optional check below. Line pressure drop, speed/flow limits and cushioning are not modelled — add your own safety factor.

Source details

ISO 15552 / ISO 6432 bore-rod combinations · F = p*A theoretical force model · Verify

Checked 2026-09-17

Standard bores

Series	Bore	Rod	Extend force @ 6 bar
ISO 6432	Ø8 mm	Ø4 mm	30 N
ISO 6432	Ø10 mm	Ø4 mm	47 N
ISO 6432	Ø12 mm	Ø6 mm	68 N
ISO 6432	Ø16 mm	Ø6 mm	121 N
ISO 6432	Ø20 mm	Ø8 mm	188 N
ISO 6432	Ø25 mm	Ø10 mm	295 N
ISO 15552	Ø32 mm	Ø12 mm	483 N
ISO 15552	Ø40 mm	Ø16 mm	754 N
ISO 15552	Ø50 mm	Ø20 mm	1.178 N
ISO 15552	Ø63 mm	Ø20 / 25 mm	1.870 N
ISO 15552	Ø80 mm	Ø25 mm	3.016 N
ISO 15552	Ø100 mm	Ø25 / 32 mm	4.712 N
ISO 15552	Ø125 mm	Ø32 / 40 mm	7.363 N
ISO 15552	Ø160 mm	Ø40 / 50 mm	12.064 N
ISO 15552	Ø200 mm	Ø50 / 63 mm	18.850 N
ISO 15552	Ø250 mm	Ø63 / 80 mm	29.452 N
ISO 15552	Ø320 mm	Ø80 / 100 mm	48.255 N

Bore/rod combinations per common cylinder catalogs (Festo DSBC/DNC, SMC CA2/CQ2) following ISO 15552 and ISO 6432. Some bores have several standard rod diameters; check the manufacturer catalog for the full set. No row is tied to a named manufacturer type code; for an order, use the datasheet of one named cylinder family.

Source: Wikipedia — Pneumatic cylinder

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Questions

What is F = p·A?+

Theoretical force: gauge pressure (N/mm²) times piston area. 1 bar = 0.1 N/mm². No friction, no seal loss.

6 bar or 6 bar absolute?+

Gauge pressure. 6 bar on the regulator is 6 bar gauge. Air per cycle uses p+1 as an absolute approximation.

Why no load factor?+

The tool finds the smallest standard bore that reaches F = p*A, with no margin (S = 1). Add your own safety factor for line loss, friction and acceleration — a fixed rule-of-thumb factor would hide how much that differs per application.

ISO 15552 or 6432?+

Follows from the bore. Ø8–25 is ISO 6432 (round, mini). Ø32–320 is ISO 15552 (profile). The smallest bore that reaches F, with no margin, wins.

Does this pick a Festo or SMC type?+

No. ISO bore and basic rod only. No type code, no cushioning, no sensor slot.

What is the rod buckling check?+

Optional and indicative: a solid rod with a chosen material and end condition, buckling length = extended length. The check is run against the available extend force at this bore and pressure (the blocked case), not the entered load. Below the Euler slenderness limit the check uses the squash load (A·Rp0.2) instead of Euler — otherwise Euler overstates the real strength considerably. Manufacturer selection tables typically use a 3.5–5x margin; use the Euler buckling tool for a real mounting.