Keep the units consistent
With displacement V in cm³/rev and speed n in revolutions per minute, theoretical flow Q is V × n ÷ 1,000 in liters per minute. The divisor converts cubic centimeters to liters.
For example, 40 cm³/rev at 1,500 rpm gives 60 L/min theoretical flow. At an assumed volumetric efficiency of 90%, the estimated delivered flow is 54 L/min. That efficiency is an assumption, not a Renowell test result.
Why actual delivery differs
Internal leakage means delivered flow is lower than the ideal calculation. Efficiency depends on the particular pump and operating conditions. Use the relevant performance data to move from an estimate to a selection.
Use calculations as a starting point
Before ordering, check the model’s speed and pressure limits, inlet conditions and fluid compatibility. The calculator below estimates flow and load; it does not check those limits.
RENOWELL · A
Hydraulic workbench
Estimate flow, power and steady shaft load, then compare two operating points.
Efficiency varies with operating conditions; leave it blank if unknown. Assumptions are not test results. Enter the required flow at the pump outlet, with circuit losses included only where assessed by the equipment engineer.
Scenario A
More information needed
Enter the required inputs to calculate a scenario.
Missing / unconfirmed: Displacement · Actual pump-shaft speed
Use these estimates for initial discussion. Confirm model ratings, inlet conditions, fluid compatibility, starting loads and motor thermal limits with Renowell and the equipment engineer before selection or installation.
Use pump outlet pressure minus inlet pressure, at the same operating point. Load pressure elsewhere in the circuit is not necessarily this difference.
Sources & method
Source content checked 2 October 2026 · recheck due 2 April 2027
These references explain the formulas. Their product ratings do not apply to Renowell pumps.
Q₀ = Dn/1000 · Q = Q₀ηv · Ph = ΔpQ/600 · Ps = Ph/(ηvηm) · T = ΔpD/(20πηm). D in cm³/rev, n in rpm, Δp in bar, Q in L/min.
Calculation scope: displacement ≤ 10,000 cm³/rev, flow ≤ 30,000 L/min, shaft speed ≤ 30,000 rpm and pressure difference ≤ 1,000 bar. These are software scope limits, not permissible pump operating limits. No universal design margin is applied.
- Parker hydraulic pump formulas · p. 2 ↗PARKER-FORMULAS · MSG30-5524-M1/UK · March 2023
- Danfoss sizing equations · p. 49 ↗DANFOSS-FORMULAS · BC518934461820en-000102 · July 2026
Includes your inputs, assumptions, missing details and formula references. After editing, copy or print the updated brief.
Calculation / inquiry brief
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References & further reading
Bosch Rexroth — Hydraulics: compact knowledge ↗For operating limits and service procedures, use the document for your exact pump and machine.