How to use this calculator
- Fix the target pressure. What the clamp, press or test head actually needs at the work.
- Divide by the supply. Target ÷ supply = required ratio; the diameters follow as √ratio.
- Check the delivered flow. Inlet flow ÷ ratio — and the duty cycle, since reciprocating units pause to stroke back.
- Verify every downstream rating. Past 700 bar you are in the high-pressure tool class — fittings, hose, gauges and the cylinder itself need certified ratings.
How it works
An intensifier is a force balance on a stepped piston: both faces carry the same rod force, so the pressures scale inversely with the areas —
i = (D1/D2)² · P2 = P1·i · Q2 = Q1/i
Pressure multiplies, flow divides, power stays (ideally) constant. The drive side is ordinary circuit design — supply pressure from the hydraulic pressure calculator, pump sizing from the pump flow & HP calculator — and the high side pushes whatever the cylinder force calculator says that pressure is worth on the work piston.
Worked example
Verified against the live calculator
A 100 mm drive piston over a 25 mm output
piston, fed 70 bar at 10 L/min:
i = (100/25)² = 16 · P2 = 70 × 16 = 1,120 bar · Q2 = 10/16 = 0.625 L/min · F = 55.0 kN
The rod between the pistons carries 55 kN either way you account it — 70 bar on the big face or 1,120 bar on the small one. Note the flag: 1,120 bar is past the common 700 bar tool class, so every fitting and hose on the high side needs a certified rating, not a standard catalog part.
Frequently asked questions
How do you calculate intensifier ratio?
Area ratio of the two pistons: i = A1/A2 = (D1/D2)². A 100 mm drive piston over a 25 mm output piston is (100/25)² = 16:1 — 70 bar in becomes 1,120 bar out, ideally. The rod connecting them carries the same force either way, which is the whole trick.
What happens to flow through an intensifier?
It divides by the same ratio pressure multiplies by — energy is conserved. The 16:1 example fed 10 L/min delivers 0.625 L/min at the high side. Intensifiers are for short, stiff jobs (clamping, pressing, testing), not for moving big volumes fast.
Why does my intensifier deliver less than the calculated pressure?
Seal friction on both pistons, reversing losses in reciprocating units, and oil compressibility at high pressure all bite — a few percent typically, more in worn units. The calculated P1·(D1/D2)² is the ceiling; the maker's performance curve is the number to design on.
Can the same geometry reduce pressure instead?
Yes — run it backward (drive the small piston) and the ratio inverts: pressure divides, flow multiplies. The calculator flags geometries with D2 > D1 as reducers. In practice dedicated pressure-reducing valves do that job; boosters earn their keep going up.
Method & assumptions
- Ideal piston-area ratio — no seal friction, reversing loss or compressibility; the manufacturer's curve sets the real delivered pressure and flow.
- Outlet flow is the stroke-average; single-acting reciprocating boosters deliver in pulses with a return pause, so duty cycle matters for anything beyond dead-end clamping.
- The 700 bar note is an orientation to the common high-pressure tool class boundary, not a code limit — component ratings govern at every pressure.
- Gas-over-oil and air-driven units follow the same area arithmetic on the drive medium’s pressure.