PSI to kg/cm²

Shopping for a Washer Rated in PSI Against a Sheet in kg/cm²

Pressure-washer shopping runs into a unit wall almost immediately. North American boxes and listings shout a psi number. Machines built for or sold into much of Asia and the Middle East print kg/cm² on the spec sheet and often on the pump casting itself, sometimes alongside bar. Two candidates on the same marketplace page can be within a few percent of each other and look nothing alike until the units line up.

The factor: 1 psi = 0.070306958 kg/cm², near enough to divide psi by 14.22. A machine badged 2 200 psi is 2 200 × 0.070306958 = 154.68 kg/cm², which is why a competitor's "150 kg/cm²" sheet is describing much the same pump.

What the Rating on the Box Really Says

Three units, one machine

The same pump gets sold as 2 000 psi, 140 kg/cm² or 138 bar depending on the market its label was printed for. None of those is a bigger machine — they are the same water leaving the same nozzle.

Flow travels with the pressure figure

A rating means little without the litres or gallons per minute beside it. Flow carries the loosened dirt away and decides how fast you cover a driveway; pressure only breaks the bond.

Maximum is not working pressure

Many listings quote the pressure the unloader trips at rather than what the machine holds while cleaning. Where a sheet gives both, the working figure is the honest one to convert and compare.

The nozzle sets what you actually get

Pressure at the lance depends on the orifice fitted. Too large an orifice for the pump and the gauge never climbs; too small and the unloader dumps to bypass with the machine screaming.

Lining Two Spec Sheets Up Before You Buy

The comparison takes a minute if you convert everything into whichever unit you think in, then look at flow and build quality once the headline numbers are honest neighbours.

Type the psi rating from the listing

Put the advertised psi in the left field — 1 600, 2 200, 3 000. The kg/cm² figure appears as you type, and the box accepts a comma decimal mark, which is how a lot of imported documentation writes its numbers.

Check it against the rival sheet

If the other machine says 150 kg/cm², you now know the first one at 2 200 psi converts to 154.7 kg/cm² — a three percent gap, small enough that hose length, pump material and warranty should decide instead.

Copy the converted number into your shortlist

The copy button next to each field gives the plain digits with nothing attached, ready to paste into a comparison spreadsheet next to price and flow. Ctrl + C while a field is focused produces the identical result.

Start from kg/cm² instead

When the sheet in front of you leads with metric, the swap arrows (↔) turn the page into kg/cm² → psi. Its multiplier is 14.2233433, so a 150 kg/cm² pump is about 2 134 psi in the language of a US listing.

Match the machine to the surface, not the biggest number: pressure that strips paint from steel will also chew render, soft timber, mortar joints and car clear coat. Standing further back and fitting a wider fan tip costs nothing and undoes far less.

Pressure-Washer Classes and the Three Numbers on Their Labels

Typical rated pressures by class, shown in all three units you will meet while shopping. A mains water supply is included at the top to show what the pump multiplies.

Class	Rating (psi)	kg/cm²	bar
Garden hose at the tap (no pump)	60 psi	4.22	4.14
Light-duty domestic electric	1 600 psi	112.5	110.3
Mid-range domestic electric	2 000 psi	140.6	137.9
Entry petrol / gas engine	2 800 psi	196.9	193.1
Prosumer petrol, driveways and decks	3 200 psi	225.0	220.6
Contractor, triplex pump	4 000 psi	281.2	275.8
Industrial cold or hot water	5 000 psi	351.5	344.7
Heavy industrial, sewer jetting	7 000 psi	492.1	482.6

Because kg/cm² and bar sit within two percent of each other, a sheet quoting 140 kg/cm² and one quoting 140 bar describe machines you would struggle to tell apart in use. The psi column, by contrast, is more than fourteen times larger — which is exactly why an unconverted psi headline looks so much more impressive than a metric one.

What This Page Does While You Compare

Run through a shortlist in one sitting

Both fields stay editable and update on every keystroke, so you can pour a whole list of advertised ratings through the page without ever clearing a box or hitting a button.

Turn it round for a metric listing

The swap arrows flip the pair to kg/cm² → psi, which is the direction you need when the imported spec sheet is the one you are reading and the psi habit is yours.

Bar and MPa sit in the same dropdown

Both unit lists are searchable across all 26 pressure units, so a third listing quoting bar or a pump-body casting stamped in MPa joins the comparison without another tab.

Readable big numbers

Thousands are separated with a space so a four-digit psi rating stays legible at a glance, while the copy button still hands over the unformatted digits for your spreadsheet.

What Buyers Ask About Pressure Ratings

Pressure or flow — which one actually removes the dirt?

They do different jobs. Pressure breaks the bond between the dirt and the surface; flow carries the debris away and rinses the area. A 3 200 psi (225.0 kg/cm²) machine at 2 gallons per minute will strip a stubborn stain faster, but a 2 000 psi (140.6 kg/cm²) machine at 4 gallons per minute will finish a large flat driveway sooner. Buyers who only read the pressure column tend to end up with a machine that cleans slowly.

What are cleaning units, and do they settle the comparison?

Cleaning units are simply pressure multiplied by flow — psi × gallons per minute in US listings. A 2 000 psi, 1.4 GPM electric gives 2 800 units; a 2 800 psi, 2.3 GPM petrol machine gives 6 440. It is a fair first sort, but it treats pressure and flow as interchangeable when they are not, so use it to build a shortlist rather than to pick the winner. Metric sheets rarely print it, which is another reason to convert before comparing.

Why did fitting a smaller nozzle change my gauge reading?

A positive-displacement pump moves a fixed volume per revolution, so the restriction downstream sets the pressure. Shrink the orifice and pressure climbs until the unloader intervenes; open it up and pressure collapses even though the pump is working just as hard. Nozzle size is matched to the pump's flow and rated pressure, which is why a worn tip that has quietly enlarged shows up as a machine that "lost pressure" with nothing wrong inside it.

A cheap listing claims 200 bar — around 204 kg/cm². Is that credible?

Treat it with suspicion. 200 bar is about 2 901 psi, contractor territory, and a genuine machine at that level has a brass or forged pump head, ceramic plungers and a serious motor. Budget units often quote a momentary peak or the unloader trip point rather than a sustained working pressure, and they pair it with a very low flow. Look for the working pressure, the flow rating, the duty cycle and the pump type — those four say more than the headline figure in any unit.

What is the unloader valve doing when I let go of the trigger?

It sends the flow round in a loop back to the pump inlet instead of letting pressure spike with nowhere to go. That bypass mode is what allows the motor to keep turning between passes, but the recirculating water heats up quickly — a few minutes in bypass can push it hot enough to damage seals. Most manufacturers ask you to shut the machine down rather than leave it idling in bypass while you move a ladder.