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This site answers one question: does this compressor give my tool enough air, at the pressure needed? Here is where the numbers come from and where what we know ends.

Data

• Every value comes from a manufacturer’s document (data sheet, manual, product page), with a link and the date we read it.
• Delivered air: we use it only when the manufacturer declares it as air actually supplied, with the pressure at which it applies. Metabo declares it at 80% of maximum pressure, and we state it that way.
• Intake air: we report it, but we do not use it to estimate the air that reaches the tool. It serves only as a limit: a piston compressor always delivers less than it takes in [68], so if the intake air is already below the consumption, continuous use is ruled out.
• Tool air consumption: from the manufacturers’ data sheets, at the pressure given in the same sheet. The Metabo compressed-air guide also gives consumption for short and medium use, described only in words, without durations or pressure [19]: we do not use them. For four Metabo impact wrenches the guide gives a continuous-use consumption that differs from the data sheet: we show both and the calculator does not pre-fill them.
• Noise: only the sound pressure level LpA, with the standard or the distance when declared.
• Motor duty cycle and lubrication: as the manufacturer declares them («S1», continuous duty; «S3» with the share of each cycle in which the motor may run; oil-lubricated or oil-free).
• Air required by the tool: oil-free or with oil, and the minimum hose diameter, when the tool’s manufacturer gives them. We show them next to the result, but we do not check them: the calculation covers only air quantity and pressure.
• If two documents from the same manufacturer disagree, we do not pick a value: we show both with their sources, and the calculator gives only the answers that hold for both.
• Archived pages: if a manufacturer figure exists only on one of its pages that now survives only in an archive, we use it with the archive date, as a statement made at the time, and the product has no shop links. This is a precautionary choice of ours: it says nothing about whether the product is commercially available.

Calculations

• Hose loss: Darcy-Weisbach with Colebrook-White [58], air at 20 °C [55][56], smooth hose [57], density proportional to pressure.
• Tank: usable air between maximum pressure and required pressure, at constant temperature. The time from a full tank is a span: the lower value counts only the tank, because the motor may restart only after a pressure drop that manufacturers do not declare; the higher one adds the delivered air at that pressure, when it is declared.
• No extrapolation: we make no estimates beyond the declared values.

What we don’t know yet

• We have not yet measured the compressors ourselves. Declared data apply to a new unit under the manufacturer’s conditions.
• The motor’s duty cycle is only partly in the calculation. With «S3» we use it to rule out: if the consumption exceeds the cycle share multiplied by the intake air, sustained continuous use goes beyond the declared cycle. The opposite cannot be proven, because manufacturers do not declare the pressure at which the motor restarts. We calculate no pauses or working times from the cycle.
• Quick couplings, filters and reducers are not in the calculation.

If the site proves useful, the next step is to measure delivered air with the tank fill-time method, publishing raw data and uncertainties.

How we choose the order

Compressors are ranked by the air they give your tool, never by commission. Some links to shops may be affiliate links: we explain this in the disclosure.